New interior

My car mustve belonged to a smoker before me, because the grey interior panel, im not sure what its called, but its above your head on the roof, it has dark brown shit stains all over it from what looks like smoking. I want to replace it. where could I find this? Its an '00 GT-S.

dealership

thanks thats simple enough. will they get a hold of a different color. like black. any estimates on a price?