linksys AP’s and wireless routers signal coverage only ranges from 50 to 100m, not to mention if there are obstruction along its way. I believe that the linksys you’ve just mention has 3 antennas? so, it must be enough to provide you at least good connectivity.
Here’s the worst for most linksys devices, their output signal power is not that great. A simple obstruction could greatly decrease the signal you are receiving and transmitting from the wireless router.
Perhaps, you can try to elevate the position of your device to widen its coverage..
Also, try to use inSSIDer to see your actual signal strength towards your device.
I have not tried this but it looks like it <a href=”http://www.instructables.com/id/WIFI-Antenna-Hack!/ “>will work for you</a>.