Apple Power Mac G5 Desktop "iphone saying disable" Questions

...iphone 4 is saying that my apple id is disabled i bought a used iphone 4 and the person who had it before me still has her info in the phone, it still has her apple id, and its not letting mines work ...

my itunes store password wont work on my iphone my 6 year old sister. was trying to buy a game on my iphone and i think she tryed it to many times so it disabled but i really need help to get it ...