Upload & Sell: Off
Very frustrating it sounds, thats a hard recovery if you don't have a backup. But, who designed the blog, etc? Wordpress isn't designed to change any of your design files, SQL databases or anything else that would effect the content on the blog. Something doesn't sound right.
The last WP theme that I used was by SLR Lounge recommended by Chris Fawkes. Lovely little free theme I must say. It worked back in WP 3.1 and 3.3. But got nuked when I pressed the upgrade button to WP 3.5.
I don't know if it was mySQL as it wasn't touched. Per Godaddy, it is up-to-date and so was PHP (gawd that sounds like a drug).
I'm not so worried about losing the formatting. But losing the blog entries would've been disastrous for me as I am not into blogging and am quite forgetful on what happened where.
IIRC what got nerfed were:
blog, portfolio slideshow, menu headings went all default, no more welcome page, logo replaced, not sure what else. But it felt like it went back to default SLR Lounge hybrid.
I've am rebuilding the site again. I planned to do this but.... in my own time. Oh well.