First of all, stop using the system immediately, Unplug it and remove the board if you have to.

If you follow that advice, then you may have a pretty cheap repair job on your hands. All you need to do is replace the caps.

If you keep using it until it really dies, then you may need to replace the entire board. You could take it to Apple and see if they'll do it, some stores are still doing it even today, but the program officially ended a few years ago.

There are some shops and individuals that are willing to do it for a fee if you ship them the bad board, so you may look into that.