Since you mention Linksys and -G, I suspect that your card has the broadcom chipset. The manufacturer will not release any information about these chips, so there are no native Linux drivers for them.
Your only hope is one of the various projects that attempt to provide a wrapper around the windows driver. NDISWrapper is one such project that I think people are having some success with... http://www.knoppix.net/forum/viewtopic.php?t=9637
But be warned, I think it is going to require a bit of tinkering to get working.