Sorry, I think you would need to have access to the actual drive or SD card you used with the Sony and pull out one of the hidden system files via computer.
It may also be just barely possible that your notes might also have been preserved on whatever computer you use to sync the reader using Sony's Reader Library software or whatever they call it. I remember giving karma once to someone in the Sony forum who helped a guy retrieve his entire library plus highlights from a backup after the software ate all his stuff.
Unfortunately, nothing currently on the market will easily let you backup/export your notes. They all want you tied into their system, as far as I can tell.
The best option I was able to give the other guy who asked is now pretty much defunct, and the best one can do for non-Amazon books on a Kindle is to save the generated .mbp + the e-book file and MyClippings.txt and manually copy them over to a computer/online storage service once in a while.
I really wish there were some kind of unified annotations open format proposal to accompany ePub (and an official dictionary format, and a pony with good resale value, while I'm wishing for things).