the original dealer that didn't do the full install is your only real option. it's not your new dealers issue, and as of Jan 1 (I believe was the date) 2007 VW/Audi no longer will pay for the retrofits. lately, VW/Audi is leaving their dealers high and dry to deal with their own problems which is why they told you it wasn't VW's problem.
Reimbursement for KIDS program claims
Dealers: U.S., Canada
Date: January 17, 2007
The KIDS Program, a special promotion which offered customers a free retrofit for child seat tether anchors for some vehicles manufactured prior to the 2002 model year, was discontinued the end of 2006. The WIN system will accept and process claims for the retrofit reimbursement only through January 31, 2007.
The retrofit parts remain available for sale and installation to ensure customers that their child restraints may be installed with the appropriate vehicle hard-ware.
Specific questions about the retrofit reimbursement may be directed to your Regional Warranty Coordinator.