I don't know where hc4361 gets his/her information from but s/he's totally wrong. You have, unfortunately, no comeback in law with a private seller.
As I pointed out, "caveat emptor" or "buyer beware" is the criteria used in private deals. It means that the potential buyer has to satisfy him/herself that the car is "as described". Another description is "sold as seen."
Unless you can somehow persuade the seller to adjust the price you paid, you don't have a leg to stand on. Sorry.