I bought an Apple branded airport card off eBay for around $15, it worked great and didn't require any 3rd party drivers. It was a PIA to install, but I didn't have any huge antennas sticking out of the back.![]()
In other threads people have reported that their factory installed MP wi-fi cards are connected to the wrong antennas. This results in terrible reception. You might want to open it up and double check the connections. I would do that first.
Failing that, OWC carries mac-compatible PCI cards and USB sticks.
http://eshop.macsales.com/shop/wireless/
They tend to be a little more expensive than most, but you get peace of mind and good support.
Well it says NOT PCI-Express! right on the web page, so no, I won't confirm that it will work.
Looks like you need one of the USB dongles or this:
http://eshop.macsales.com/item/Linksys/WET610N/