Covering a residance colony over 2 KM

I have an area round about of 2 KM where i want to setup WIFI. The solution which i have is to set up
15 DBI Omni
Outdoor Access point
4 Watt Amplifier
I want that every person in the area of 2 KM can get connected to wireless having simple wireless lan card without any external antenna
is this rigt or if you have better solution please tell me
regards

I feel Each Client will need an Antenna as well, as the ones built into Laptops etc are Very poor, and over 2km

if your looking at spending some money, they you could look at something like this: Go Wireless NZ 802.11 Wifi Omni Antennas