I did a quick Google and found this thread in which someone apparently did manage to enable LPR/LPD in Windows Vista (to share a printer with OS X) so it should be "possible", but... it is Windows we're talking about. As for alternatives I can't think of much. There's a company that sells an AppleTalk server suite for Windows called "ExtremeZ-IP" , but the price is positively breathtaking. ($800 for the cheapest license.) Another company called "Cyansoft" offers separate print-and-file service software packages. (The print server is "cyanPrintIP") No idea what their pricing is as the website doesn't say, other than claiming it's an "inexpensive" way to set up a Mac print server. If it's "inexpensive" by corporate standards that's probably still way more than you want to spend.
If you had a Linux box lying around (Or... I guess if you were willing you could run Linux in VMware or Virtualbox on your Vista machine and get really clever) you could install Netatalk to share the printer and resolve the issue that way... Anyway, hey, at least the solution *sort of worked*, right? ;^b