mac os x 10.6 cannot create admin account

[makalanilee]

i just rebooted my computer using the disk and it changed my admin account to standard user. i tried to boot in single user mode to create a new admin account but i can't type anything. i need serious help. i need to access my itunes, but it says it was created by a newer version. so in order to access my library, which has all my contacts and everything for my iphone, i need to upgrade or update my itunes, but i can't because i do not have administrative priveledges. i am in serious need of getting that information cause i had just backed up my iphone and sent it in for repair. i received it yesterday, but i have no contacts. HELP!