I solved my screw problem, the plastic screws can be replaced with 9/16 x 1.5" metal bolts with a washer. Same thread, same length. Works just like the plastic ones. You will need to find a fastner distributor in the yellow pages, since they are not at the local home depot.
I could use 3 hinges as well. Pending finding the hinges I took a zip tie, wrapped it around the tube shaped hinge on the door and pushed the fat end of the tie thru the hole and the thin part aound the edge of the door and hooked them together on the inside. I was surprised how well this worked and how securly it held the door on the building. I usd a screw with a fender washer to simply cover the bolt hole left by not having the original hing