I live in San Diego and had that exact problem in
my 20-year-old stucco house. I finally gave up and
ran network cable throughout (not an easy task,
I guarantee you).
Like the other poster
said, I ,too, can connect to my neighbor's unsecured
WLAN just by walking outside with my notebook computer.
If my house did not have the wire mesh, I could
probably get away with not even subscribing to broadband