well, there's any number of wifi usb dongles to use from your local
office supply superstore or electronics retailer (just check for basic
linux compatability and try for an atheros chipset if you can. also
there are 4 versions of the wifi cape, last I checked digikey they had
the version that does 802.11abgn with either onboard or external
antenna. shop around, seems you'll find a supplier that has these
capes in stock.
Eric