there exists already a wifi plugin that works with prism chips...but it's not easy to get it work. Atheros chips are currently not supportet.
I currently also try to compile ralink wlan drivers for dreambox 70x0.
The easiest solution is to use a Game-Adapter(Netgear WGE111) or use a linksys or similar router with linux firmware that is able to run in client mode.

If you are interested in wlan and linux here some links:
linux wlan project
Linux and WLAN(de)