Hey guys! I'm an intern right now and my boss wants me to create a 3D model of our college's main statue. But I can't seem to get the hat right! Is there anyone here who could tell me how to fill in these holes? I'm an extreme novice here and any advice would help.

Here's a picture of it:
Screen Shot 2017-06-09 at 8.51.08 AM.jpg

Here's the file: