The Car Corral Sold me a car that's falling apart and they refuse to fix it. San Antonio, Texas

The Car Corral sold me a vehicle that seemed fine until I had it for 2 days, then the service engine light came on, called them they said they fixed it. Went off for about 3 days and came right back on, tried contacting them never received any response, finally the car dealership said it was because of the gas cap, replaced that and still didn't turn off.
 I was starting to become okay with it, because I was already used to it. Then my tire became flat, they told me they placed new tires on the vehilce, (this is about 3 weeks after having my car), so they said they would fix that. Picked up my car a week later, after having to pay for them to put 2 new tires on, drove to Austin and my roders were going out so bad my car was going to sieze up, (per the mechanic) he also told the owner of the dealership. They towed my car from Austin and repaired it, not my fault it was theres.

Now, my service engine light still will not turn off and my horn has went out again, and I barely ever use my horn so I can't seem to understand why it's not working when it's not a fuse. I called the dealership they said I have to go repair that myself. Called Evelyn, a lady that works there and she was completly rude and told me its my responsibilty. I can't afford to go to a mechanic and my inspection is up this month, how am I suppose to get all this fixed.
Informed Evelyn that I've never been late and I always pay extra on my car payment, asked since I'm having so much trouble if I could just trade the car.. She said I would need to put down a new downpayment and everything I have paid on my vehicle will be veto'd. I did tell her I would be contacting the BBB after she told me being a valued customer doesn't matter. Got the owners cell phone number and he forwarded my call and has yet to call me back.

Poor business, and poor customer service. My parents purchased two vehicles from them and both have had to been takin' back becasuse there is nothing but problems. That place is a hoax, and I can't believe I'm stuck paying on a car only worth 2,600 and it doesn't even work right. 
This is just wrong!!!!