Probably way too late, but - I have the same card, the same distro, and had the same problem.
dxqcanada is right. If your card isn't working with the prism driver, then it is a different version using a different chipset.
First, blacklist the prism54 driver so it won't load every time you insert the card:
sudo gedit /etc/modprobe.d/blacklist
Add the prism54 driver.
My card has been working well and reliably on an old Thinkpad T21 using ndiswrapper. There are tons of wikis, support threads, and how-to's on setting up ndiswrapper - several very good ones on the ubuntu forum. Not hard to do, if I could manage it I'm sure you can as well. I can't do WPA level security for my wireless network, but the connectivity has been good.