Dang. I was hoping for a little something to make it a little easier. I know it's tough. And I hate that you're having to face one of the (few) negative aspects of chicken keeping so early on. Good for you for making a tough decision though. Just gotta try, try again! Best of luck to you.
Have you ever had problems with the other? He will take over the spot as flock leader since his competition is gone, but if he hasn't shown any aggression towards you at this point, he won't necessarily be bad. But he may too. Personally, if he's not shown any aggression towards you whatsoever...
I agree with Jed and Chickassan. There are people who say to try holding them, tipping them upside-down, giving them a solid kick etc. My opinion is that it just agitates the bird more and gets your hopes up. He may remember it for a while, but it is doubtful that he'll do a complete 180 and be...
I'm sorry to hear that your new flock has given you some bad eggs! The unfortunate fact of the matter is that an aggressive roo is an aggressive roo. He won't get better. Roos that have the audacity to charge and attack a human should not be kept. Aggressiveness tends to be hereditary in poultry...