Car financed what should i do?

i financed a car from a lot i put like 1000 down an my other car which i got 1000$ credit for it so i put 2000$ down pretty much well after 2 months it needed work no big deal the lot fixed it free of charge then 2 more months down the road it messes up big time i take it in an they say the engine is shot an at thispoint im still paying my weekly payment i decided to keep payin cause they said if i come up there they will give me any car in the price range of my other car which was 13000$ i had already payd 4000 on it so they said i can pick a car "around" 9000 well i went in to pick a car i found one i liked it ran good it was 9500 so i felt out all the paper work but at the end they told me u cant take the car u need to put 200$ down an pay ur weekly payment i sadi i will pay my payment but refuse to put 200 down an they said it was impossible for them to give it to me then so i told them id think about it they havent called me in awhile but at one point they said they could sue me i was wonderin can they or if they dont try should i sue them formy money back???????????