Wireless cards in linux is not seamless as ethernet cards due to the propriety nature of them.
Here is how I got broadcomm to work on Mint 13 awhile back.
You will need to activate additional drivers
1. Go to Menu
> Control Cente
r > Additional drivers
Choose the broadcomm STA driver and activate. Reboot if ask to.
If you don't see broadcomm STA driver, do this from a terminal as root
sudo apt-get update
sudo apt-get --reinstall install bcmwl-kernel-source
Now repeat step 1 above. Wireless should be working now. This simple step has worked for me.