I had a similar problem with sound not working properly on my laptop and desktop. Download the newest alsa-driver from alsa-project.org and install it. If you plan to use backtrack only on your laptop run ./configure before installing. However, if you plan to run on multiple computers check out ./configure --help to set option for different audio cards. As far as the problem connecting to wpa/wpa2, I'm not sure how to configure the wireless assistant, however if you use the terminal window, have a look at the commands wpa_passphrase and wpa_supplicant.
Copy your wpa_passphrase output into /etc/wpa_supplicant.conf
$ wpa_passphrase myssid waylongkeythelongerthebetterbecausewecareaboutsecurityalot
If you need a little more explanation I found this information by typing linux connect wpa into Google and clicking I'm Feeling Lucky.
# iwconfig eth1 essid "myssid"
# ifconfigup eth1
# wpa_supplicant eth1 -c/etc/wpa_supplicant.conf