Same exact thing happened to me two weeks ago! I had the same harwood hood. My hood is pretty flimsy now but I was able to glue the top and bottom pieces together. It's ok now but my new paint job was ruined. I bent the cowl panel back into place witha board and a pry bar. Looks ok. You can get a plastic cowl vent at this site for 69 bucks.
http://www.latemodelrestorationsupply.com/
Sorry, I feel your pain!