I take it by "overburn" you mean overheat? If this is the case, and damage is evident, then you have no choice but to change it.
You can pick up some good cards relatively cheap nowadays. About 6 months ago, i picked up a nvidia 7600GS 256mb for my work computer, and its proved brilliant. Mixed with 512mb RAM, a 3.0ghz P4 and the card, i decided to install LFS and see what the performance was like. I got 95FPS average, on Fern Bay, with 8xAA and 16xAF @ 1280x1024 res. I would definetely reccomend this, or a GT as im very impressed with it. I got the GS for £40 from PC world, so im sure you could find one cheaper somewhere.