Most wireless ISP's only allow contact for users within the same house.. Is yours different?
Generally though, when distance is an issue for a wireless connection, I test with another computer and verify if it's the computer at fault, etc.. And when all else fails, a high gain antenna, or a directional antenna on the router or computer seem to take care of the issue.
Hope this helps.
My mom has an older PC, HP Pavilion A300Y,it's running Windows XP. She has been sharing my wireless connection (houses side by side) recently the computer cannot locate the the wireless network but says its connected. What should I do?