My Wi-Fi is a menace

No, not because it’s frying my brain or making my testicles grow to mammoth proportions; it’s just rubbish. I’m typing this on a laptop that’s about 20 feet away from my wireless router (the router’s upstairs in the office, I’m downstairs on the sofa), and after about 20 attempts at turning airport off and on again I’ve finally got a one-bar signal. It’s the same with my Xbox, which is about ten feet away: sometimes I can get a signal, most of the time I can’t.

I suspect the problem is a combination of my house’s construction – it’s a 1940s job, built in solid brick – and more recent changes such as the two extremely big reinforced steel joists that hold the roof up. But whatever the reason, my Netgear 108Mbps router simply isn’t delivering a decent wireless signal downstairs.

Can anybody recommend a Wi-Fi router that (a) works with Airport and (b) doesn’t lose its signal when faced with a couple of brick walls? Or a way to add a wireless repeater so I can get a decent signal in all of my house?