The best advice I can tell you is to do it the other way round and look at wireless cards available, then the specifications and see what the chipset is (sometimes referred to as chip or logic).
It can be hard, but, if a shop isn't going to help you, go somewhere that will and fire a presales question and ask them!
If you are really struggling, attempt to look at high resolution pictures of a card on the manufacturers website.
For example, I see you are in America from your profile and I know people talk about Newegg. I went to the first wireless card I could find, zoomed in, and I can see that this uses a Ralink RT2860 chip
Unfortunately, a lot of cards have a big plate over the chip so you can't see it. But, I hope this helps you a little or puts you on the right track to finding a card.