You need to sign in to the App Store app and "claim" your free iLife apps. They should show up there on a list when you login to the App Store app the first time. If they don't then you have the issue kensic described.
or what you can do is download the iLife suit from somewhere and when the AppStore looks to update the Apps it now automatically adds them to your purchased Apps as if you paid for them (same with Aperture)