Setting up free wifi for 500-1000 meter range.

Setting up free wifi for 500-1000 meter range.
Theres a farmacia here in the Dominican Republic (Samana) that wants to setup free wifi for 500-1000 meters range. He wants it to be open access, but when you get onto it it will pop up one advertisment page for his place. then u can surf the net for free while out and about with your laptop or at a resourant etc. The town is made from moslty cement buildings 1 - 2 stories high. *His is 2 stories* Its near the ocean (his is less then 500 meters to the ocean i think.) He tried to do wifi now but just with a low end router and its not working well. I guess im wondering about equipment and how to setup that popup page/when u try surf the web. Or if theres a place that already explains all this. i have limitied access to the internet so it makes research a bit more difficult. So im interensted
  in ideas, (cheaper is better, but it needs to work.)
I did get on the chat online and they mentioned doing a 4 or so directional AP's to a central router (also with wireless on the router i guess to pickup the local dead spot) Someone thought 4 corners of the building for the AP's instead of trying to make a tower. The problem i see is that it seems hard to find directional antenas that have a wide degree spread, i guess i would need 90deg on each at least.
Any ideas or neat/new equipment or specific parts would be appretiated. We can order stuff in if need be, or try local/what we can get. Im not sure on his price range or anything. Ill just work with what i get from feedback. 
Ive never taken on a public wifi project before, and never these ranges either, so any help is help.
 
wes
[email protected]
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