Since all the Firefox bookmarks are in one file (bookmarks.html), the easiest thing to do is to find that file and copy it. Use the directions I gave earlier to find it.

Once you made the mistake of cutting the bookmarks (I'm assuming you were in Firefox's Bookmark Manager?), you could easily have gone to Edit/Undo. 

You also learned a valuable lesson about the limitations of the system restore. It only restores system settings. Firefox's bookmarks are not part of the system. Nor are any other data files you might create.