Moving from Dropbox to iPhoto

Okay, so I'm pretty new to using Mac products, and I'm having trouble finding the answer I need already posted on message boards here. I need the video to be accessible on iPhoto so I can upload it to a certain app I'm using (called Autismate). The video is currently in Dropbox on my iPad, but I can't figure out how to get it over to my camera roll. When I try to share the file via Dropbox, my only options are using email, text message, facebook, tweet, or copy to clipboard. Any help would be appreciated!