I need to save clash of clans to game center

I got a new iPod for Christmas, and I have to give the old iPod away. I downloaded Clash of Clans onto my new iPod, and I dumbly started a new game. I logged into my game center after that, and for some reason it attached to the brand new game. Now I don't have a game center linked to my old iPod's account, and I want to transfer it. I've tried making new game center accounts but they won't save to my old iPod's account. How do I save a game center account to my old Clash of Clans village?