Where do I find out about the LEMON LAW on used cars?

I bought a 1995 Plymouth grand voyager 3 weeks ago and have had nothing but problems since. The supertine belt broke the day I drove it off the lot and then a week later it wouldnt start (no warning) and now it seems as the transmission wont shift. I dont have anyother transportation and I was wondering since the dealership will not repair it (still under 30 days) if I could get my money back and get something else or if i can make them get me a good car.?