is it a built in or a plug in wireless card? I'm thinking since you
specified Broadcom, it's a plugin. Though someone here may have the answer
for you, You might solve it quickest by finding the model number on the
wireless card, and running a google search for "Ubuntu Broadcom
wireless" and see what sort of hits you get from the ubuntu forums. Its a
good chance there is a post with several options on those forums or this
list.