Is the USB adaptor for connecting to a 3G network for Internet access ? If it is, then you need to look for a MiFi router. The MiFi router will connect to the 3G and also provide a local WiFi network for you to attach your wireless devices so they can share the 3G internet.
Have a look at the WhatIs article for more information.
Hope this helps.
I have the same setup here for years. There are many brands of routers that are not specific to any one service provider, and does not limit the number of devices you can connect. I use a cradlepoint which has many intresting features and also allow wired connections. You can use the Mac filter to stop anyone from “borrowing” your connection. Go to cradlepoint.com to check out their current routers.
and for more info.