Wireless routers

ok, im doing an experiment... i have a wireless router on the end of my house, and a pci card in my friends computer nextdoor.... our rooms are on the same side, so there closest, so what im trying to do is set up a network, which im able to do everythings working fine at my house (he had his compy over here) 100% signal and all... anyways he carried it to his house and he still has a signal like 40-50% however all the sudden it drops, its really sensitive due to how far away it is... is there anyway to increase the signal... like just using around the house or very cheap methods? its only for lan gamming and sending files back and forth.. no internet....

with the signal he could see a server i was hosting on my game but i refreshed it again and it died idk if it was something software or what however i moved his antanna ..... i know theres such thing as high gain antannas but i dont wann pay 50 dollars for them...so is there anyway to boost it... ? using cheap methods... people rig fans and stuff all the time so theres got to be something for this... ?
tx

http://www.turnpoint.net/wireless/cantennahowto.html

This might help ya out.