I bought a 96 cavalier last week. The head gasket was leaking as I could smell antifreeze on day 2. They acknowledged it was leaking and they "patched" it . Will that suffice? Also, if I blow the gasket will it kill my engine? What should I do? I am still under warranty for another 3 weeks.

You bought this from a dealer and they offered a warranty? If so, then I wouldn't consider a patch an acceptable "fix." A leaking head gasket on this vehicle is usually caused by engine overheating. The only way to permanently solve that problem is to remove the head, have it planned and reinstall it with a new gasket.

12 yr. old car with a warranty?? Want to buy a bridge over the Atlantic?. cheap... If that's for real, make them fix it! By patched, if they threw in some blackk pepper and plugged the leak, that'll do long enough to keep you out of their hair! I wouldn't even settle for any kind of head repair job. Worked in a professional shop where they fixed heads by drilling and tapping threads into the crack, over and over again until they thought they fixed it, and then they'd magna flux it, and it all would look good. Just to be sure, we'd pressure check it by plugging all the holes, and putting air to it. 9/10 of the time, it'd still leak (a little if not a lot) Then to fix that, they'd just peen it(which is basically bending the metal together "mashing" it with a ball peen hammer)until it dtopped leaking. I know metal, and I know it expands with heat, and contracts when cooled. How much of that do you suppose that mashed together crack would handle before it started leaking again? Make them replace the gasket, and have the head checked for cracks, and planned. If there are any cracks in the head settle for nothing less than a NEW head!
Good luck