AP's, routers, Gateways?

I was looking at getting a linksys wrt54g (see link below), which is a router, which would be good (I asume) if I wanted to connect to the wellington WLAN as a client, as I could just set up someone else's AP as the gateway on the router and point my antenna over their somewhere and hopefully it will connect using DHCP or... now I am confusing myself.

But in order to become a "part" of the WLAN (ie: not just a client), what I really need is just a HUB right? something like the dlink 900AP+? so that anything that connects to my AP will still be on the wellington (I mean nation-wide *cough*) WLAN network and not my own local wireless network, so that anything that connects to my AP, whether it is a server I set up or someone walking down the street with their laptop (likely scenario, or some other house down the street that wants to connect to the WLAN by connecting their AP to my AP, will be a part of the WLAN.

ok, can someone clarify this for me, I have links to 3 products I am thinking of buying below, I think the dlink would be best suited to this scenario.

cheers

http://www.dlink.com/products/?pid=22
http://www.linksys.com/products/product.as...?prid=508&grid=
http://www.3com.com/prod/en_AP_AP/detail.j...sku=3CRWE554G72