Where tobuy/find the Airport card replacement?

Hi,

I've been looking around Amazon, Newegg, eBay and other sites to find an Airport Extreme Card for this model of MacBook Pro, but I can't seem to find one. The internet is littered with cards from 2008, 2009, and 2011…it's as if my model doesn't even exist. Where would you recommend looking for a card or, alternatively, where can I actually buy one?

Ever since I got this Mac the airport would intermittently shut off and would require a reboot to band-aid the issue. I've had Apple attempt to diagnose it…but they "couldn't find a problem" and I'm far out of warranty now. I've tried all the tricks in the book; just looking for a card.

Thanks,

Josh