restore previous version

Hello. I have been editing a Prezi that was created by a peer in my college course. This is for our group presentation. I tried to add a new image and when I did, almost all of the content from our Prezi was wiped out. I immediately clicked on the undo button but nothing I did would bring the content back.

Please, please help! If someone could restore this to the version that was saved at 1:00 am EST on 12/11/13, that would be wonderful. I think my error occurred around 1:08 am.

Also, is there a way to fix this myself?

Thank you.
Christine

Link to Prezi:

http://prezi.com/xg5itbp_ztht/copy-of...