There are much cheaper solutions which will provide the same functionality. I just bought a higher power usb wi-fi adapter along with external (omnidirectional) antenna for all of the $40 (as a bonus it works with my Mac).
Pretty much any usb based adapter with higher power (300-500 mwatt) and external antenna would do well. Antenna can be placed remotely connected to adapter with the wire (and adapter can be connected remotely using long usb cable).
Here is an example:
LONG RANGE WIRELESS-G USB adapter kit for Apple Mac NEW - eBay (item 110211730589 end time Jul-03-08 16:14:42 PDT)