That's sooo terrible! I can't even imagine how your must be feeling... I think one of the suggestions to look around in dumpsters or ditches nearby is worth a shot after you file a police report. Most guys (men) have no idea what the bag is worth, and probably just wanted your wallet/cash and phone. He may recognize the LV pattern, but you may be able to find your bag.
Oh gosh... I feel so awful for you - I can't believe no one did anything!