Networking my Toshiba RS-TX20 Wirelessly

So i bought a RS-TX20 DVR TIVO system a couple months back and am just getting to hooking it up.. but i cant get the thing to recognize my usb wireless adapter i bought for it.. the adapter works great on my pc, but doesnt help with the tivo.. i checked the tivo site, and it wasnt listed.. but i cant seem to find a place to buy any of the ones they listed as compatible.. is there any workaround for this that you know of? i dont really want to shell out another $50 to get their Tivo Brand Adapter.. seems like a ploy to make more $$$... thanks in advance