Mac G4 10.3.9 to Dell Laptop Windows Xp Via Airport

[Graphicwit]

I have a G4 450 running 10.3.9 with 768 MB of RAM. My wife has a Dell Laptop running Windows XP. My daughter also has an iMac running 10.3.9. We do own a copy of PC MacLan, a few years old, and we have an Airport Base Station. My wife does have a wireless networking card.

Currently, my daughter and I are able to use the DSL via Airport connection, but we can't get my wife's computer to pick up the network.

I'd like to connect our computers through Airport so we accomplish 2 basic goals:
1. My wife's Dell can utilize our Mindspring DSL connection through Airport.
2. My wife's Dell can exchange files from either my computer or my daughters computer. I don't think we need to see everything on each other's computer. A file sharing folder on the desktop would be fine.

Could you please just run down the HOW TO of setting up our computer settings, etc? Thanks.

R. David Robinson