Ok for the first one...

The major thing you need to find out is how to log in to your router. The way it works is go to a computer that's connected physically to the router and open IE or Firefox, some browser. In the address bar you're going to need to enter the IP address of your router. You should be able to find it in your original documentation that came with it. It will look something like

Type that in and you should get a username/password prompt which is set at the factory (and you should be able to locate as well) to something like User: admin Pass: Password.

This will take you into the router and it's configuration. If you've been using it already for non-wireless...there's little you must change.

You should have a wireless settings section, make sure you have these set up:
SSID: It has one (you said KB439...), so you can either just make a note of the name of yours or change it if you'd like to something different. For now, I'd make sure you don't have WEP, WPA, or equivalent security with keys on..because that will just make it harder at first. Make sure that you have "Radio" enabled if you have that, and that you enable "SSID Broadcast."

Now the laptop should be able to connect, given it is configured to access an open dynamic DNS type access point, with DHCP enabled. As far as networking both PC's, don't go do the same thing to the other PC like the wizard recommended. Just get one computer working on the router, then go mimic EVERY setting on the second computer. As long as you make sure that each computer is using the same Workgroup name...be in MSHOME or something easy like WORKGROUP. Also make sure that you've enabled sharing of whatever folders on each computer you wish to share. If you can't find one of them on the "view workgroup computers" thing, try searching for it by it's name (Case Sensitive). You can verify/change both the name and workgroup of a computer by right-clicking on My Computer for properties. Then go to the Computer Name tab....hope this helps.