Edimax EW-7811UN USB adapter missing wifi APs

I am new to Backtrack and Linux as a whole. (minimal experience)
I installed Backtrack R2 on a Lenovo X60 tablet which has the Intel 3945ABG onboard wireless card.

I bought a Edimax EW-7811UN USB wifi adapter at a good price, as i saw it mentioned that it supported packet injection and was good for Backtrack.

I was not seeing any Wifi APs which were showing up on my Intel card, so I found mention of using RealTek Drivers. I followed these instructions: http://www.r-statistics.com/2011/11/…-ubuntu-11-10/

I installed them, but when I did a wifi Scan, only 2 of the numerous APs in the area showed up.

Any help?