Maybe look at using
NdisWrapper, which lets you use Windows drivers. Gentoo have a package for Ndiswrapper as well. See
this list of cards known to work with NdisWrapper. There's an entry for a card with the same model number as yours and the revision is given as B1 and for said card, there's a native Linux driver so you may not need NdisWrapper yours is the same one (see the link to the driver on the page).
