Paint & Body Work - quarter panel patches

is there a place where i can get patches for the quarter panel? or do i have to buy a whole new quarter? mine is rusted all the way through. and im in the process of fixing the whole car.

ok upon investigating with a wire wheel i found out it was bondo... an inch and a half thick that had cracked... im rather pissed off now... who ever fixed it from its previous wreck has no business doing body work whatsoever!!! they didnt even try to get the dents out. they just covered it up with body filler.