why dont you revert your computer to before you installed BF3? you'll have your saves back then.
360

aaaah.....sorry to hear. best i can offer is to google search recovering deleted data, digital data is never really deleted and can always be recovered if you know how...(i dont mind you)
edit: alternatly you could simply start a new game when 1.4hits or if its hit consoles already you can simply start one now the upsides to this are alot of quest fixes where sent out aswell as the ashpile fix....try a necro or a archer/necro or something, and next time dont delete your saves

or....save your saves onto an External HDD, you can do that from xbox cant you? (i know you can form ps3..)