Instead of trying to improve conditions on the client side, it would have been more wise to improve conditions from the AP side. To get adequate coverage in my house, I have 4 AP's scattered throughout. One in the detached garage, I have an WRE54G in the backroom that links to a WAP54G that's in the pantry, and then there's a WAP54G that bridges into the same WAP54G in the pantry.
I have excellent coverage through out the entire house no matter where I go. When I get done wardriving for the day, I pull buggy into the garage and upload my data right from there instead of hauling the PC inside.