iPhoto 11 is a marketing name. The actual version of iPhoto is the ninth, hence you have 9.4.3, that is, iPhoto 11. You don't need to purchase, and you can't now anyway.
Go to the App Store and check out the Purchases List. If iPhoto is there then it will be v9.6.1
If it is there, then drag your existing iPhoto app (not the library, just the app) to the trash
Install the App from the App Store.
****
Sometimes iPhoto is not visible on the Purchases List. it may be hidden. See this article for details on how to unhide it.
http://support.apple.com/kb/HT4928
One question often asked: Will I lose my Photos if I reinstall?
iPhoto the application and the iPhoto Library are two different parts of the iPhoto programme. So, reinstalling the app should not affect the Library. BUT you should always have a back up before doing this kind of work. Always.
I can not find my smart albums on photos, or a way to delete a bad photo once it is imported. Any actions that it can do are hidden and not easy to find.
Enable the Sidebar. Deleting is the same as iPhoto, pretty much, as in basic: select an image, tap delete...