There's a couple of ways. A quick google will reveal any amount of recovery software you can download (take usual precautions downloading off the web), install and attempt recovery, which you may want to try first.
That said, given how important your proposal photos will be to you, if that doesn't work, I'd be tempted to do another google for Data Recovery Specialist and then get them to do it for you, assuming you don't mind them seeing what's on there.
http://www.alphr.com/blogs/2013/10/16/how-to-recover-photos-from-a-corrupted-memory-card