Sorry, but if you did not save your bookmarks then your bookmarks will be lost. When you upgrade everything on your computer is removed.

I had the same your problem and I resolved it. You just need to download Firefox lasted version at http://www.mozilla.com/en-US/firefox/all.html and setup normal (Don't uninstall your Firefox old, you have to override in your installation process . All add-on, bookmark and ... won't be lost. Good Luck!!!