Since you haven't mentioned your Ubuntu version,i can't give you "exact" instructions.
Ubuntu can install third party drivers via the "Hardware Drivers" app.
Try finding the app,if you can't then open a terminal and run this.its command for the same app.
It will search for drivers on your system(may take some time). Then you should see driver for your wireless card.Click on activate.Remember that it will not work right away,you will have to restart your computer.After the reboot it should work.
Note:You will need Internet access to download the driver so plug in a wired Internet connection.I downloaded and installed driver for my Broadcom b43 wireless card using the same method(i used a usb wireless card to connect to the hotsopt)