It will work thru the USB, but you have to load drivers and set it up for USB only. It won't do both at the same time, and you gotta reconfigure it to go from one to the other.
Routers are pretty cheap. Wireless routers are sometimes even cheaper than regular routers. I've got a 2 yr old Linksys BEFW11 802.11b wireless router I'd part with pretty cheap. I'm using 802.11g these days. I even have a signal booster to go with the 802.11b that it still cellophane wrapped in its original box. Not sure what kind of coverage area you need, but with the booster your neighbors on all 4 sides of you can probably connect via your setup (you can lock them out of course).