I'm a novice but this is what worked for me on an acer aspire 3000 with the same wifi card - not sure if all the steps are completely nessesary but i'll include everything just in case:
1) Clean install
2) You should get an "install driver" notification on the status bar - I ignored that for now and applied all the ubuntu updates first.
3) Install the b43 driver either from the status bar icon or admin>hardwaredrivers
4) activate driver in admin>hardware drivers
Now you need the firmware for the wifi card so use fwcutter
5) In terminal use command sudo apt-get install b43-fwcutter it automatically fetched and installed firmware in correct location.
6) Then it worked!
As I said - I'm a novice so somebody else could probably point out the difference between what I did and what your doing - you my not need a re-install - maybe just fwcutter???