What kind of card is it? With linux are you just using a livecd or do you have a full install to play around with?

For Windows, check out the Airopeek site. They have a pdf of all compatible cards. You won't be able to go promiscuous without it. Windows doesn't allow setting the cards to promiscuous if I remember correctly.

I'm sad to say your only option may be to get a new card. I screwed around with a few different cards before I could get it to work, including one with Linux support. That's with just getting it to load, not even setting it to promiscuous.