Can you open a command prompt and as root run the command 'lspci' and post the results. First thing is to see if the card can be seen by linux. I think that card is an Antheros chip set. If it is, that will show up in the command lspci. You will need the Madwifi drivers installed to support the card.
Post back the results, we'll go from there.
Here is the link saying Madwifi supports your card.