Please run the terminal command:
Is your wireless device ID 14e4:4331? If so, please download this file and transfer it to your Ubuntu machine on a USB key or similar. Drop it on your desktop. Right-click it and select 'Extract Here.' Now back to the terminal and do:
sudo mkdir /lib/firmware/b43
The folder may already exist; that's fine, just proceed.
sudo cp Desktop/b43/* /lib/firmware/b43
sudo modprobe -r b43 && sudo modprobe b43
Your wireless should now be working.
If this is not your device ID, please post it and we'll proceed.