Each part of the iLife suite carries it's own version number. Easiest thing is to check what version of iPhoto you're using. Find it in the Finder (Applications folder), select it, and hit File -> Get Info (or Command-I). If it's 9.x, then you have iLife '11. If it's 8.x you have iLife '09.
If it's an Apple refurb, you have '11, though. They always ship with the latest version, and it's been more than long enough to not have to worry about the overlap period.
jW