You'll get best reception if you have line of sight between the basestation's antenna and your own antenna. Do you know where the base station is located? If so make sure that your antenna is facing it with as little as possible in between.
In South Africa I've used a wireless provider who was a few kilometers away, by having a big antenna on the roof. And in fact, that was just a relay station on the top of a hill, which then beamed the signal 40km to Capetown. This was all using bog-standard wireless routers, but good antennas.