First off, I am new to Linux/Ubuntu, and I barely know anything about it. I know this was answered on the web many times, but I tried all I could find, and nothing worked. There is no way I could access internet inside Ubuntu, as wi-fi is my only source of connection. I am dual-booting it on a MacBook Pro Retina (mid 2012), if that's any useful information... Another thing is that when I open System Settings>Software & Updates, and enable "Cdrom with Ubuntu 13.04 'Raring Ringtail'", and open the additional drivers tab, I see "Broadcom Corporation: BCM4331 802.11a/b/g/n", and below it says "This device is not working.". If I enable it, it just reverts back to "Do not use this device".

I have also tried the n43 solution, and a whole bunch of terminal commands that I found on the web, to get it working. I had no luck so far. I'll put additional information if I need to.

Thank you for your time.