Exterior Wifi Super Antenna

I need to build a dish for a friend so he can get WiFi from about 200 meters.
I have several dishes to work with my problem is the antenna will be at least 30 feet from the computer.
I will use this linksys usb  i would like input on the idea of a usb to cat 5 to stretch the usb cable? should i power the linksys from a powered hub ? the build will be posted on instructables when done and i will give credit due.
my parabolic gets about a 14 db increase from a WiFi usb thumb it just puts the thumb into the sweet spot of the dish and is not for the outdoors. I an open to any and all suggestions tomorrow i will post what my db are from the site .

Picture of Exterior Wifi Super Antenna