Hello burluck
The iLife suite should have been pre-installed on your Mac when you purchased it and would not need to be installed. Check your Application folder or look in the Mac App Store for those apps to either update or install.
Alerts may occur when accepting bundled applications from the Mac App Store
http://support.apple.com/kb/TS4373
About updating iPhoto, iMovie, and GarageBand
http://support.apple.com/kb/HT4710
Regards,
-Norm G.