Hard Drive Disappeared - Recover Data?

Hi there,

I was working on my MBA (bought Jan 2013) when all of a sudden it froze and shut down. I was in the middle of trying to do a back-up. When I turned it back on, a blank gray screen appeared and eventually a flashing file folder. I took it to an Apple Authorized Reseller (I am in Cambodia - no Apple stores here!); however, they said there is nothing they can do to recover the data and I need to replace the hard drive. I am desperate for my MBA to be working again, but even more desperate to have the files back as I was in the middle of my thesis.

What options are there to recover the data on my own (the store said they couldn't do anything)? Should I recover the data before sending my Mac in for service?

Thanks very much!