NOTE: You will need an internet cable to connect to the laptop until the wireless card is working.
Open the Terminal application and type the following:
This will update the repositories and tell your system where to get the drivers from.
sudo apt-get update
This will install the driver.
sudo apt-get --reinstall install bcmwl-kernel-source
Now reboot the laptop and try and check the system to see if you can connect to the internet with the wireless.