I believe i had the same problem.The thing is that propietary drivers dnt come with the installation, for some law blabla pretty much someone wants a profit somewhere i guess, anyway.....
1) click on control center from the menu button.
2) go to Other (last option)
3) There Ull see Software Sources click on it...
4)Click on Additional Drivers (Top right last tab)
5)Select using Broadcom 802.11 Linux STA wireless driver source from bcmwl blabla
6) Enter, let it do his thing and voilà
7) Enjoy and look up in you tube The summerian scripts documentary Very Interesting....
Peace!!! (drops mic)