HELP ME PLZ !!!

while i was at the Pik n Pull i found a sunroof of a hb an decided to put it on my coupe ... well as i measure an start cutting out my roof i finish and start putting in the frame of the sunroof which i end up finding out its just like half an inch too big and well yea i guess u can say i fkd up
but how can i fix this ??? PLZ HELP !!!!
p.s i dnt got a welder an was thinkin i could fiberglass like a piece of metal or just use plastic filler to make that inch or half an inch go away??? 


