How long after I put a down payment on a car do I have to take it back?

Basically what happened is I am getting married in January but i didn't have any transportation to get from my college to my home town, which is 2.5 hours away. So, i went home and my mom and i saw a few cars at a lot. we went to the lot called the owner, i had my uncle and grandpa with me just in case. So i found a Mitsubishi Eclipse that the guy had drove up there and he said that he would be willing to sell it to me. All he asked was for 1000 down and 100 every week. I was apprehensive, but my mom test drove it and so did the manager to allow me to see how much power the car has and also that it didn't have any weird sounds going on. The car has a salvaged title, but he ured me that there was nothing wrong with the car. So I give him the money on Sunday and drove back to school Monday morning. Now, it started to rain and come to find out...my windshield wipers don't work! I have to have something under the trunk opener because if I don't, then I'm not able to open my trunk on my own. Basically you need one person pulling the lever and the other person opening the trunk @ the same time. There is now a clicking sound whenever i put my feet on the gas. There isn't any kind of radio, just a big hole, which i was fine with. There are 4 different brands of tires on the car! 4! The driver headlight is dim and not as bright, i told him and he said something about playing with it a little bit to make it work. Now, the total cost of the car that he is asking for is 5900...now he Kelly Blue Book Value of the car in excellent condition is 5100! I don't understand why I am paying 800 more for a car that obviously needs some serious work. The interior is dirty, which i can't necessarily fault him for since he drove to the dealership in it, but i did expect him to clean it. Ok, now here comes the interesting part, we have not done the title transfer because the car is registered until Feb. 2011 and the inspection is good until Feb. 2011. I've had the car for 3 days now and i wanted to know if there is a way i can get my money back? I just don't feel as if i should have to pay $400/month for a car that I'm going to spend double or triple that getting everything fixed for it. I wasn't trying to take the easy way out, but with no credit and no co-signer its very hard to get a big dealership to work with you. :-( I just needed some transportation to help me plan for my wedding better. I thought having family there would prevent me from being in this situation, but apparently not.