Two points/questions that occur to me:
Is the Kindle's USB a master USB? I mean, can it power the WIFI adapter?
Tivo WIFI adapters are ... kinda big ... and they connect via a cable. Might a smaller flash-drive-like WIFI dongle be a better choice?
I'm not all that familiar with the Kindle's workings, or I might have a better idea of the answers to those questions already.