how do i change my reset info email for security questions?

I have forgotten my security answers for my ipod 4th gen. 16gb that i recently got on 1/12/13. I set a security password that i didnt need for about a year but now i do. I dont remember what the passwords are and i cant figure out how to switch the passwords. i sent it to the email address that was posted for it to send and did not recieve and email on the subject on the passwords.