by linux not supporting it, i presume you mean you can't get in to Xwindows? if you can still get into the system and boot up on a black screen, then that's not linux, that's X. and recompiling a kernel will have absolutely no effect whatsoever. You gotta appreciate how modular linux is. I seriously doubt there's ANY graphics card that can't be used outside of X.
actually, i just had a search around, and i saw somewhere, mention of needing 2.4.8 of better. i'm dubious about that, but you can download the mdk rpm rfor 2.4.13 kernel from rpmfind.net and upgrade your current one to that one.
there's also a rage128 howto around on the net, look for that for more details on how to actually get ati cards working nicely.
i had a ati Xpert 2000 for abuot 2 days, and couldn't get it to work ever, and found that it was officailly unsupported in an way. so i swapped it for a nice geforce2