My dad and I switched iphones.

[Liniwa]

I'll try to explain my dilemma in the shortest form possible. My dad had a 3rd generation iphone for years, I finally got my own iphone in January 2012 (iphone 4 8GB). I soon found out mine didn't have enough space and at the same time my dads old iphone broke when he dropped it. He decided to take my iphone 4 8GB and i bought a new iphone 4s 16GB. the at&t guy switched our phones over. when i got home i connected my old one to my itunes to save all my apps and everything and then hooked my new one up and transferred everything to the new one. the problem is my dad's keeps asking him for MY itunes info even though he's logged out and logged back in, and its asking for a voicemail password which was never set up by me or him. should i connect to itunes in a whole other computer with his? i'm just trying to get all my settings out of his phone except for all his contacts. and thats the main thing, if i reset it what does it keep as far as information goes, if any?