The XP Pro machine was my work desktop and is now my work laptop. Unfortunately I can't hook the printer up to that.
It's not drivers that's the problem, it's that the machines aren't on the same network. They don't see each other. Until I was just able to map the network drive between PCs via the IP address last week, I couldn't even share files between PCs. I had to copy files from the home machine to the MAC (via the map network drive solution) then from the MAC to the work PC (again via a mapped network drive).
So even if I hooked up the printer to the XP Pro machine, I'm not sure the XP home machine would see it on the network.
Of course, you must understand that I have no knowledge about these kinds of things other than what I've tried by trial and error, so there's probably something I'm missing. At this point I'm going to wait until I get a new PC in a year or two and figure it all out then.