I'm not sure if this will help your problem, but have you installed the latest updates for both the Airport Extreme and your MacBook Pro. that may be a good first thing to try
this week Apple released Airport Client software update, and a few months back there was an update to the Airport Extreme itself too. check Apple's site for the latest downloads
I don't recall exactly when, but my MacBook Pro (2006 vintage) had Wi-Fi reception problems at first, but there was some update along the way that seemed to fix it.