Ah what a paint in the ass!
You got any more pics of it all? It still sounds salvageable, changing a sill is not easy. Plus when you take them off its quite destructive, so if you did manage to get one of another car it would require alot of hammering and bending for it to fit yours
They don't make repo panels for coupes I'm told
As well as that, welding and filling where it meets the quarter would be very difficult indeed
