I am trying to set up a WIFI networking system for our complex that includes 25 condos. I put a wireless "N" router in the main office which is suppose to go directional 1200 feet. But for some reason either because of walls, etc when it gets out to the farthest point it loses it signal. I put an expander that is a "G" expander and it isn't being picked up well. MOst of the people in the complex have "g" receivers. How can I improve the situation so that people can connect through walls, etc. Is there a better "expander" system?