Just cause the dude is a bouncer and you were outside the bar does not mean he is allowed to assault you. I'f you've got one witness I'd take it to the cops and have the prick arrested for assault. You may not get him convicted but you'll put him out he cost of a lawer and some time/headache. I'd probably go after the bar for some compensation too. Fuckers need to be held accountable for the actions of thier employees then perhaps they'll think twice about hiring morons (probably not but you can hope)