Hi
your question is pretty much "generic linux" howto question, not much related to eddy module.
It is definitively possible to use USB Wifi sticks with embedded linux as well, but you have to work a bit modifying the build configuration and tweaking it to work, this may be not a trivial task unfortunately there is magic "do this" and the xyz wifi dongle will work on xyz embedded linux distribution.
Start by comparing the configuration and build make of the eddy and the ubuntu system in places related to usb and wifi-network
best of all if you manage to create a linux installabel kernel module (.ko file) that supports your wifi stick, then just copy it to the eddy filesystem, and make sure it is loaded at startup with insmod command
Antti