It all depends on how attached you are to the car. $1000 for a headgasket is a good price, but the mechanic hasn't seen what is wrong on the inside of the engine. Once the head is off the price is likely going to go up substantially.

Cavaliers are rolling pieces of tinfoil. They fold like paper in crashes, and the engines are not that reliable.

If you are looking for a used econobox, I would suggest looking at a civic (reliable, good on gas, relatively cheap) or a Focus. New I would suggest a cobalt, (very good reviews) Focus or a civic.