Hi, I just set up an airport extreme, and everything is great, except the fact that ONE computer is in another part of the house and can't receive signal. It's an old house, thick walls, some kind of metal foil inside them. I have been looking at the antennas offered by Apple, but they all say extend range, where what I need is to make my signal stronger.
Also, I don't want to order one of the antennas, have it not be what I need, and be stuck with it.
Any ideas?
Thanks.

The metal foil inside the walls is likely part of your insulation.. a water barrier backing.. if that touches part of the electrical system it makes a nice ground and makes RF difficult to pass. The high frequency Rf from an airport usually works pretty well. You can't change the amount of RF power out from the airport, besides it is a two way system...

Your best be might be a wireless hub system that you could maybe move a bit closer... or might be fine on it's own. You should be able to find someone with one close enough to borrow one and try it. Installing cables point to point is also an option, but it is not fun in an older house.

The good thing about trying an external antenna with more Db of gain is that you can move it in different directions and maybe find a hot spot that works well... change it to vertical .. or rotate it where it is..