Xbox Live NAT problems

Hey all. I''m having trouble with Xbox Live; after a few minutes of gameplay, I'll lose a connection for no apparent reason. The Xbox Live customer service guys tell me it's because my NAT is "strict" where it should be "open." As you may have guessed, my router is an Apple Airport. Now, I am mostly clueless about wireless LANs and how they work, but I do not wish to go buy a whole new router just to play Xbox Live games, however, I'm wondering about a few alternatives before I scrap the Live account:

•I've heard of "port forwarding," which apparently helps get a server established from an individual computer on a LAN using NAT. Could this help my Xbox and if so, how might I go about doing so?

•The only option I'm given other than getting a new router is getting new firmware, though I undertsand my firmware is the latest for this Airport. Anyone know of a way to fix this NAT problem?

Thanks for any help.