iCloud doesn't store movies or music. It only allows you to redownload purchases from the iTunes store if you ever lose them (assuming they are still available to redownload, and in the case of movies, that the studio permits it.) Also iCloud only stores your camera roll photos in your backup, which can only be accessed by restoring your iPad to the entire backup.
iCloud isn't designed to do what you are trying to do. iCloud is for syncing data across all your devices and for backing up your devices, not storing your data. You use iTunes on your computer for that. iTunes will add your purchased videos and music to your iTunes library so you can remove it from your iPad and add it back later if you want. To save your photos you import them to your computer (and then delete them from your iPad if you want) as described in this article: http://support.apple.com/kb/HT4083.