You might not need a router. I have 3 machines connected by D-Link wireless connection. All run XP-home. My ADSL modem and printer are plugged in (by USB) to the slowest machine, that is virtually all it does and it shares disks, printer and internet connection, it also runs the firewall (which took forever to configure). I bought a router which sits on my sideboard as a talking point as it is of no use.
Everything works fine, all the systems share drives and all share the printer and modem.