Hi
There is two thing that you should consider about the Public wifi project. One is, if you want to cover the whole area that you specified, is there any building, trees, statues, or whatever on this area? each thing acts as source of interference for the wifi spectrum.
The second thing is, if you want to cover density of user on the wifi, you will have to implement a little bit more Access points, bridges or repeaters on the infrastructure.
The best way to do this is by doing a site survey on site, maybe I can help you with this. I work for a Cisco Partner in Central America, so I'm used to do this kind of job, however,I'm a new on the freelancer world, that's why you see no rate on my profile.
I'm also own the Wireless specialization from Cisco, so I believe I'm a good candidate for this project.
Hope we could do this work together.
Best Regards
Alvaro Rugama
P.S. sorry if my english sounds weird, English is not my native language.