Sorry to say it mate but your roof is fooked. only way to fix it is to put on a new roof skin because you cant mend them once they have gone like that as they are a double skin.

The rest doesn't look that bad so some welding would sort that out but it's the roof thats the main problem, good luck mate. Look on the bright side, your car is still sitting on its wheels, my esc cos is but a bare shell in the garage getting its winter rebuild