iCloud does not give you more storage on your device. The capacity of your iPad was fixed when you bought it. iCloud only syncs your data and photos to other devices and backs up your devices (if you choose to do so).
To create more free space on your iPad you need to delete some things. You could, for example, import your photos and videos to your computer and delete them from your iPad (see http://support.apple.com/kb/HT4083). You can also adjust your sync settings in iTunes to reduce the amount of music and other media stored on your iPad.