National Auto Sales Car Fell apart 3 months after getting it Marietta, Georgia

I bought my car, a 2004 VW Jetta in April 2012.

Not even 2 months later, the check engine light comes on. The alternator is going out and so is the cataylic converter. So now, I'm having to spend around $600 on repairs. 2 months after I bought the thing "fully serviced".  

The radio only reads CDs sometimes. Oh, and about 3 months ago, the interior has started coming apart. The cloth hangs down off in chunks from the ceiling. It's hanging off the doors. I'm going to have to have the interior redone. 

It's HORRIBLE. I wish I had never gotten a car from this place! And their customer service is extremely rude and uncaring. If I could, I'd give the car back and go somewhere else.