When having a Wireless Coverage problem that seems to be out of boundary.
I.e. The distance is much less then expected.
1. Get an Hold of a Computer that has Wireless card and can be easily moved
around (Like a Laptop or PDA).
Read this: http://www.yqcomputer.com/
And install Netstumbler on the portable computer.
Put the Wireless client in a distance and start to play with positioning of
the Wireless Source (Wireless Router, or an Access Point).
It might be you would find a spot that would provide better propagation.
While using the client with Netstumbler as your reference device.
2. If it does not help or the spot that provides better signal is not in a
practical place to put the Wireless Source in, you might need additional
hardware to provide better coverage, the content of the following links
May be this can Help.