Andrew,
The rental company is going to go after the easiest target...you. It is much harder for them to go after the guilty (uninsured) party. You should contact your insurance company, and let them fight it out with budget. That's why you have insurance. Since you have legal proof that the accident was not your fault, you will not get dinged for the damages. They MAY come after you for the deductible, but if it were me, i would tell them to stuff it and turn me over for collection...frig 'em. I would also hammer on the dealer, but sit down with the OWNER, not the service manager and explain the whole thing start to finish. My guess is that he (or she) will try to help you. Especially if you did not get nasty and rude with the people at the dealership.