best (cheapest) directional WiFi antenna for ~1KM?

[DaCoOlNeSs]

hey guys, we need a directional anntenna for my job, and I am the one in charge of buying it because I am supposed to know everything about computers ( ) so I need the cheapest best weatherproof antenna for 1KM or less.

Thanks in advance,
-Keith

 

[0ldman]

14dBi RooTenna @ wisp-router.com

weatherproof enclosure with 14dBi panel built in.