First thing I would do is search the forums, since this is a subject that's been beaten into the ground.
But in an effort to help:
Post the output of the following command :
Which version of BackTrack are you using? This may not matter, but I'll assume BT4.
lspci | grep Network
It sounds like you uninstalled the driver that came with it. Reinstall the first driver (that the distro came with) and do the following, since I'm guessing you never tried it:
THEN try to use Wicd to connect to your wireless network. One of the biggest things I'm seeing with the new folks here is that nobody uses the 'ifconfig...up' part, since in most (all?) major distro's (and windows, and OSx....) that part of the job is done automatically.
ifconfig wlan0 up
If you've already tried this, however, we might have bigger problems. The only way I could get my Broadcom 4318 to work in Ubuntu was using ndiswrapper...it works great, but for injections I'm pretty sure it would fail.