You said, "i know it is against the law for them not enforming me about it".
I doubt that there is any law requiring that a seller of any used car disclose its prior history, unless a statement to the contrary is made. Would you please provide some support for you claim of this notice being required???
The online website for reviewing NJ statutes is currently not available (apparent server problems on their end) so I am not able to review the current statutes. The only related site that I was able to find indicates some specific rules for the NJ used car lemon law, but there appear to be a lot of exceptions and caveats. For example, was your car purchased 'as is'?? If so, that would limit some of your normal rights.
http://www.lemonlawclaims.com/usedcarcases.htm
Also, don't just settle for 'the lemon law' as your only recourse. This may very well be better regulated as a consumer fraud issue, if you can show that the dealer knew, or should have known, of the prior damage.