Not sure how to install a driver and which driver to use - or whether I could do something in terminal. I'm pretty sure there's no driver there already but I might be wrong. I'm running a dell mini 910 inspiron off of a 32gb usb with ubuntu 12.10 installed.
I go to System Settings, open up Software Sources, go to end tab Other Sources and there is where I turn on the Broadcom wireless card.
Hope it works for you cause that's how I turn mine on running from USB.