can i upgrade to a new phone?or not?what would they do?i have att.?

[AmandaPlease:)]

Alright so I have had my phone since May, and the charger piece is broken and it doesn't charge sometimes. You have to hold it or put it in a certain spot. I really want a new phone but i don't know if it is possible for me to get one. Is it? My service is att, and i want to know if it is possible for my to get a new one. (a different phone) What would i need?
thanks