All good in theory. Even if you can find someone else with an XP disk (any one will do) it may not boot. The Windoze installer checks for the boot flag, and dies (quietly) if it doesn't find exactly one partition marked thus. Easily enough fixed if you're handy with Linux tools.
Best solution might be to go get supergrubdisk
and use that to boot into the first (recovery) partition. Should be all automagic after that.
I now refuse to buy laptops that don't come with a full OS licensed CD/DVD; this is just such a stupid situation to put users in.