Comment # 14 on bug 903525 from Bernhard Wiedemann

(In reply to Guillermo Luna-Victoria from comment #12)
> I have the same problem but with a medialink MWN-USB54G. ans I don't have
> access by cable to Internet. Any alternative? Download into another
> computer? Download from direct dvd? Buy another card without restriction?
> Please HELP.

if you cannot get network any other way, you would need to read
install_bcm43xx_firmware

you can probably download things elsewhere 
and copy them over USB... or you get a non-broadcom WLAN device