I was just wondering if it is considered a lemon..

My husband and I bought a car from Jd byrider, and I have been on this website a few times.. I have had some issues with my car since i got it. A few months after I got my car I ended up having to take it to my mechanic, b/c their so-called "warranty" is crap! Anyways, he takes one look at it and says it has been in an accident. So I am already kinda pissed, then he tells me that he thinks that the frame is twisted from the accident it was in before I bought it? What can I leagally do to them? Thanks!