Retrieving Simpsons game

I recently upgraded my iPhone from the 4S to the 6 version, and my "Tapped Out" game effectively reset itself back to zero, losing all the stuff I built up in 2 yrs. of game play.

I still have it on my 4S, but deleted the new and NOT improved game from my v. 6.

Question: How do I retrieve my Tapped Out/The Simpsons game for my iPhone 6? Is there some way to transfer the original game from my old iPhone to my new one?