If you don't have anymore GB's left on a iPod touch but have space on iCloud does that mean you have more space
The space in your iCloud means that you still have space. However, you can always buy more space to upgrade your iCloud storage every year if you want to. See http://www.macworld.com/article/1160380/icloud_what_you_need_to_know.html for reference.
The iCloud space is only used for backups of things like contacts, iPhone/iPod backups, photo streams, etc. you cannot use the iCloud space to download more app and stuff.