The problem isn't your WiFi cards but wicd itself, it's probably trying to switch to your ethernet connection which isn't available causing you to get disconnected from your wireless connection.
Switch to nm-applet and the problem will go away.
You might have to fix nm-applet as well.. if you come across any problems try this..
apt-get install network-manager-gnome NetworkManager
killall -9 nm-system-settings
And run nm-applet again.
Hope this helps!