I helped someone out with a similar wireless device under Ubuntu
recently. You might try using the native driver (bcm43xx) instead of
ndiswrapper. I believe you will need to extract the firmware from
the windows drivers. There's a debian package called bcm43xx-fwcutter
which will do this and put the files in /lib/firmware.
(Instructions at http://www.debiantutorials.org/content/view/153/213/
also mention that it might be good to copy *.fw files from /lib/firmware
to /lib/hotplug/firmware the author doesn't sound too sure about that.)