| I take it you mean the usb port? You should be able to get a usb hub to give you more usb 'girl parts' to put the 'boy parts' in, and they're not terribly expensive but it depends on what you need. I doubt you'll need to spend more than $20 for your needs, going on the prices we have here in the UK. Maybe they're cheaper there, most things are.
As for your friend's copy of XP, I think microsoft are way fussy about unregistered copies, etc, so you might have problems with it unless you've got a valid unused serial/key for it. I don't know much about all that though, and there are probably ways around it, maybe Mike can advise. What I do know is that you might not be able to get windows updates on an unregistered copy of XP, and so unless the copy of XP you're being offered is fairly recent (so comes with service pack 2, I think?), you might run into overall computer problems, that I'm too much of a novice to specify. Just talking pretty general.
It's worth checking your machine has the hardware capable of supporting XP as well, I don't know quite what XP requires but I'm going to hazard a guess that it'll be more than ME. Check your hard drive, RAM, processor, perhaps? Again, bit of a rookie here and maybe it's gonna be okay, but it's worth checking?
Edit: haha, Mike managed to beat me to it on all counts, and with fewer words.  | 
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