Needing some advice after years of not buying a car seat

I thought our car seat buying days were over...until this morning when I decided to do some early fall cleaning and wash up the seats prior to a car seat shuffle.
I have 4 kids ranging from almost 11 to 3 years old. My oldest is giving her booster seat to my 6yo and the 6yo will be giving his harnessed seat to the 3yo. The seat that the 3 yo is currently in will be expiring at the end of this year. And my 8yo is sticking with his Diono booster.
It wasn't until I noticed in my cleaning that the harnessed seat that would be going to my 3 yo expired at the end of 2013! I had no clue! I totally assumed that since the seat that my 3yo has been sitting in was bought in 2006, that it would be the first to expire. No big deal though... She still has her seat and it's fine until the end of the year...so that's just one new seat to buy. But then, I noticed that the booster my 11 year old had been sitting in had a manufacturing date of 2008/12...and Sunshine Kids expire after 6 years. So, looks like we're going to have to get another booster for my 6yo. We're pretty sure on getting him a Diono like what my 8 yo has but I'm stuck on what to do about my 3 year old.
I haven't bought a harnessed seat in years! The last one I bought was just as the weight limit was pushed to 60-65lbs from the old 40lbs standard.
She's a good 35lbs and roughly 40 inches tall. Any suggested seats that will give her a good 3-4 years more harnessed. I'm not really looking for one that turns into a booster so that's not necessary....at that time she could possibly move into my 6 year olds if he's done with it.
Thanks!!

I'm completely lost. Can you fill in the blanks please?

Kids

11yo (I'm assuming) passes the 5 step test
8yo in booster-
6yo currently harnessed ready to move to new booster Weight/Height?
3yo currently in-what? Needs new harnessed seat. 35lbs and roughly 40 inches tall- rear facing or forward facing?

Currently owned seats

Diono booster- which one and manu date?
what other seats and what are there dates?

So you have a Diono booster that is still usable, and a Sunshine Kids booster that is expired? What are the other seats?

Your children are all moving into the next stage? Your eleven-year-old is now sitting without a seat, your eight-year-old is staying in his Diono booster, your six-year-old is moving in the booster your eleven-year-old was using (what is this seat? How old is it? Is it backless or a high-back?), and your three-year-old is without a seat?

Is that correct?

I'll break it down...

11 year old - no seat needed
8 year old - in Diono booster...no change
6 year old - getting 11 year old's old SK Monterrey which is expiring in December 2014...will be getting him a Diono booster like his brothers before then
3 year old - was to be getting the 6 year old's harnessed Safety First seat which has since expired back in 2013 and will be on its way to the dump next week...but for now is staying in her Alpha Omega 3 in 1 which expires in December 2014 - she'll be needing the new seat

^ was me unregistered. I have since found my old username and password from 2010. It is so much easier this way.

Anyways, yes my almost 11yoDD passes the 5 step test very easily. She's quite tall.
My 8 yoDS is in a Diono Monterey high back booster...it's only 2 years old...lots of life left.
My 6 yoDS is in my 11yo's old Sunshine Kids(pre-Diono) high back booster...expires this December.
My 3 yoDD is in a harnessed Alpha Omega that expires this December.
So, my 6yo and 3yo are needing car seats. I'm leaning towards getting another Diono booster for my 6yo(46lbs, 46"), and possibly a Nautillus for the 3yo. Suggestions/recommendations?
My 3yo was weighed last night and is 38lbs, 41" tall.

No space saving is required...always in a Toyota Sienna.

About the Alpha Omega, is it the older one with the 40# max on the harness, or the newer one with the 50# max on the harness. If it's the old one, and his shoulders are below the top usuable harness position (which is actually the second to top position the headrest can actually move to) he has a tiny torso and you won't need a super tall harness seat to get him to booster age and you'll have other options.

The Diono is probably a good choice for the 6yo since you know and like it already.

What kind of budget are you working with?

It is the older Alpha Omega that goes to 40lbs. We pulled it out of the car to clean it and checked as I hadn't needed to adjust it in a while. It is on the second to top level...I can move it up once more in the harness position. In my opinion, she does have a long torso for a 3 year old...she wont be 4 until February.

As for budget, I'm hoping that TRU has one of their baby equipment swaps before the end of the year, but I'm seriously doubting it since Christmas is coming. That being said, any Christmas money from the grandparents are being put towards that. Then again, I don't want to spend money like it was growing on trees, but safety is important to us.

Thanks for any input or suggestions...I'm feeling quite overwhelmed to be looking at the numerous options in seats again.

I have heard rumors that the Monterrey is coming back, but it had been discontinued in favor of the new Diono Cambria, which is just starting to ship. So far, the reviews look favorable.

The Nautilus, Evenflo SecureKid, and Harmony Defender (although it's hard to come by right now) are all good options.

jess71903 said:

I have heard rumors that the Monterrey is coming back, but it had been discontinued in favor of the new Diono Cambria, which is just starting to ship. So far, the reviews look favorable. The Nautilus, Evenflo SecureKid, and Harmony Defender (although it's hard to come by right now) are all good options.

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We don't have the Defender in Canada so scrap that. For budget friendly seats look at the Evenflo Sureride/Titan 65, the Evenflo Maestro or I've heard some Superstores are clearancing Graco Nautilus seats.