I may well be mistaken because I hadn't even heard of 802.11g until a few weeks ago, but I thought that a device like the Linksys Wireless-G Broadband Router might do the job... <<<<<<
I'm not convinced. £100 routers are designed to be THE wireless hub on the system, which is fine when you just want to serve a few mobile devices or to avoid cabling. But they provide the infrastructure that chooses which channel to use and how fast to shovel the data down it, so I can't see how they'd work with another (bigger) one across the road trying to do the same job.
I too may be wrong in all this, either because I'm missing something fundamental or because 802.11g is different to 'b' in some crucial way. But I have two WAPs and they've never seen each other, let alone set themselves up as network bridges. Least, there's nothing in either manual to suggest how to do it.
And now I'll shut up and hope to hear from someone who really knows about the subject. It's a bit off-topic, after all.
-- GT