Technical Update/ Free High Speed Internet

The little town that I live in has installed a free metro-fi network, but my wireless network card does not really pick up the signal. The closest network access point in on a lightpost 100 yards from the house. I broke down and ordered a WIFI modem with a directional antenna that should do the trick. I need to look into the security issues of using a free WIFI network. I have file sharing off, and a windows firewall, but there is probably more sophisticated security measures that I don't know about.