How to fix my dented in volume buttons?

recently, i dropped my iphone and it fell on it's side; coincidentally where the volume buttons are. however, the fall had caused the damage of pressing in the one volume button that highers the sound/ringer. i also noticed that a piece of the phone somehow dented, making the process of popping the button back in place a lot more harder. is there a way the one button can be fixed so that i don't need to buy a new phone? if so, what would the usual price of doing so may be?