'2 square kms' and 'a small area' are not synonymous terms with respect to personal wireless network. As Ankit stated above, only professional business entities can provide you that kind of coverage.
If that was a typo error and you are looking for a smaller area coverage, please read on. I am currently using a wireless router that provides me wireless coverage upto 200-300 metres without any issue. Its a TP-Link 300 Mbps wireless N router with the model number: TL-WR940N.
This particular wireless router comes with 3 powerful antennas and gives me good coverage in every corner of my house. I can also access my WiFi network even while roaming in my colony. However, the network goes out of coverage if I go further than 3 houses on either side of my house.
If you are looking for an area coverage like this, I would suggest you this particular router. However, if it is indeed 2 sq. km radius that you need coverage for, go ahead and speak to companies mentioned by Ankit.
Here's an overview of the router I suggested: