So here's a free way to get Vista: Download it(like the trial version) from the Microsoft website, and install it(or some Torrent site). When it prompts for activation, click later or something(make it go away). Then according to Tech-Recipes.com:
1. Press WinKey + R to open the RUN box
2. Type or Paste this command into the run box:
3. Press OK or hit ENTER
4. After your next reboot, vista will give you 14 more days before requiring you to activate again.
Supposedly you can keep doing this forever, which means that you have the full version of Vista on your Mac (because I know you don't use PC's right?) The only problem is that you may not get the security updates if you use this technique, but hopefully you won't need to run Vista to much.