My woes were solved in the seaside UK flat - 4 damp walls between me and a free router - by borrowing a usb arial amp device. I've posted on it before.
However, even that would not have been good enough if I'd not had inSSIDer 2.0 Fabulous freebie, which spelled out that moving the antenna just one inch could knock out the neighbor's signal, and raise mine. Obviously, it gave me guidance on which channel to uses.
Darn BT signal from nearby was sometimes spanning from MINUS 3 - to plus 4, either side of one-ish. Total PITA. Here in Texas, I've got it on the telly's computer and again just an inch or so makes all the difference. Putting a CD disc behind it knocks out some neighbor's signals.
All of this I'd be blind to without this or a similar program.