I am letting my downstairs neighbor use the wireless signal from my WRT54G router. The problem is, she does not receive a usable signal unless she is out on her deck. This is because to make it into her apartment, the signal has to pass through a 20" thick steel-reinforced concrete floor. When she is on her deck, she is receiving the signal through my windows.

A cordless telephone also fails to transmit a usable signal between levels.

It is not practical to drop an Ethernet cable down to her level.

What would be the best and most cost effective method of improving her signal strength?

tanstaafl.