This is not the first time this has happened. Get a lawyer to take the case on contingency. If your story is correct you will win on gross negligence alone. The last one of these stories I read the guy ended up with a 3 year newer model car out of the deal plus some cash in his pocket for the trouble. This is why the dealership carries insurance.
Does this not fit this case perfectly?
n. carelessness which is in reckless disregard for the safety or lives of others, and is so great it appears to be a conscious violation of other people's rights to safety. It is more than simple inadvertence, but it is just shy of being intentionally evil. If one has borrowed or contracted to take care of another's property, then gross negligence is the failure to actively take the care one would of his/her own property. If gross negligence is found by the trier of fact (judge or jury), it can result in the award of punitive damages on top of general and special damages.