I can't find the updates tab in the mac app store (just updated iTunes)?

I'm trying to purchase a book of photos through iPhoto - it tells me to update iPhoto before I can order the book. My macbook pro is running OSX Lion so it says I can update iPhoto "in the updates tab of the mac app store"... but when I go to the app store in iTunes, there is no updates tab. I then tried the second update option, via software update under the apple menu, but that just updated a bunch of other firmware, not iPhoto.

Can anyone help point me in the direction of the iPhoto '11 update please?