How to change my iTunes settings on my iPhone?

So I got an iPhone 4 last week and we set it up using my dad's apple ID. My dad and I share an iTunes account but have desperate apple IDs, however I couldn't remember mine so I used dads, assuming it would be fine since we share an iTunes account anyway. (I already had an iPod touch before I got my iPhone). But now my dad and I (dad has an iPod touch) share notes, internet bookmarks, contacts etc. So that when one of us ads or deletes a contact the same thing happens on dads iPod.
How do I fix this? Do I need to create a whole new iTunes account, copy all my music to the new account, then completely reset my iPhone and sync it to the new account. That seems an awful lot of hassle, is there any other way?
Also, please explain it simply, I'm not amazing with computers: L

Just remove your dads apple id account and create a new one or try to recover the password for your exiting Itune account.

Once you have done the above, connect to icloud on your iPhone sync your iPhone with icloud and everything should be aright.

How this is of hep to you.

Also if al fails you could just start over. Here is a video on how to do that: