You can set up the base station from your Mac even without an Airport card installed. You will need to install the admin utility onto the computer and physically connect it to the base station (use the LAN port on it). I've done it before, and it is NOT difficult to do. Read through the guide/manual that comes with the base station, since you will need the initial admin password to get into the base and set it up.
Get a network switch, plug the LAN port into the switch and you can have as many computers/printers on the network as you have open ports. I have a game pc here at home, as well as a network printer connected through the switch to the base station. I can go online from either the game pc, or my TiBook (800MHz with the airport card installed) and print to my Epson C80N (from either/both computers).
With the switch, you can also have LAN parties, both wired and wireless if you desire.