Bear with me if some of this sounds stupid

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Before I continue, I'm "assuming" an access point gives you the ability to extend a current wireless network without hardwiring. Am I right / wrong?
I have a client that wants to setup a 54G wireless network. There will not be any 802.11b NICs on it.
My questions are:
1. What is the best "real world" 54G wireless router within a reasonable price? By "real world" I mean download / upload speeds and signal strength @ 100' unobstructed distance.
2. Which routers allows for access points?
3. I'm not sure this is possible (never tried this before) but can I set the router up, find the point where the signal starts to drop, install an access point there and boost the signal another 100'?
I've been reading reveiws for the past few months on the 54G routers but I need opinions from people who have actually used them. I setup a Belkin 54G router for a customer a few weeks ago and had the worst luck gettting it to work. I wound up replacing it with a Netgear 54G router and it worked fine

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What is the difficulty level of setting up the router, and say, 5 access points, and getting it to play nice?
Opinions, comments, linkage welcomed!
TIA!
Mike