Listen, no, you aren't going to all be able to be together as one family again.
You aren't. Certainly not in the near future.
That's just a fact. If you do then you'll probably lose your son.
So you have a choice, you can stay apart from the mother of your son, and see your son regularly and eventually build up to unsupervised contact.
Or
You can get back with your girlfriend and your son will be taken into care.
That's the way of it now, because of the violent argument you both had.
If I was you I'd choose to put my son first. Go on all the visits with your son and cut all contact with your ex. Not even a text. That way you'll be able to keep your son.
I know you love her and it's hard. But that's what happens when you have violent arguments with people in front of a baby.
You don't need a new woman right now, no one has suggested this. People have suggested that you concentrate on being a dad, cut all contact with your ex and that way you won't lose your son.