OK, we have some ideas on to help you. Are you mechanically inclined? Do you feel like you can do your own work? If not, do you have anybody locally you can trust? Get a code reader and arm your self with knowledge: Amazon.com: Actron CP9125 PocketScan Code Reader: Automotive is just an example. I have a more expensive version of the same thing that allows me to reset and get rid of the check engine light.
1) you can fix the car yourself and lower your overall cost of ownership and get it fixed correctly.
2) Go ahead sell the car yourself to get the best price (don't trade it in!)
3) Go to a trusted non-gm mechanic and get your car right.
Pick a plan and let's get you satisfied with your car. Option 2 is just a valid way of being "satisfied" What would you like to do?