Bought a used car from NYC and they forged my signiture on the bill of sales!?

i recently purchased a car and made a deal with them to take the car off the lot for $15,000 even. And he would put it on the road and switch everything over. Well he did all that i went down there to Queens, NY and picked it up. He didnt even ask me to sign anything and i just drove away after the plates where on and i got the paperwork. i thought it was weird but didnt think much of it. Then soon found out he checked off [AS IS] on the sales receipt. And forged my signiture which looks nothing like my name. On top of that they wrote the car being bought for $7000 for tax purposes when my bank made out a 15,000 check directly to there dealership. On top of all that there is alot of things wrong with this. The transmission is blk and smells burnt. the headlight mount needs to be replaced. there is a grinding noise on the left side. the heat motor is blown cause it hums loudly. The glove box is all cracked and broke. There straut/shocks need to be fix.Then there is a metal noise while accelerating. He claims he is gonna fix it but i dont think he is gonna. What should i do?