I have a 2012 iMac that I just got a notification on that i'm completely out of hard drive room. I have a ton of music and pics mostly. I also back up to an external. What are my options? Do I move some of my stuff over to the hard drive permanently? If i did that I'd have to keep the external on all the times I would guess, is there a problem with that? Can I have an bigger hard drive installed? Is that something I can do or do I have to take it to Apple?