I'm very sorry this is happening to you. I do understand how you feel, I've been through much of what you have been through, and might I give you something to think about.....
I understand you were frightened, and so you should be. Your boys have wittnessed enough too. They are probably just as frightened for you, yet, don't really know how to express their feelings. Let them know you are okay, give them a big hug, let them know they are safe.....
With this, I second the Officer's sentiment, fill out the papers for the Order. Bring your Friend as a witness when you do so, have her include what she saw.
Secondly, demand a neutral place for exchanging the children. This is something you can do, even on your own, however, it might be best if you get your attorney on it too. I found exchanging the kids outside the Police station kept the negativity away from my home. In front of the Police station keeps everyone on their best behavior too. You can ask for an escort, and an officer will be sent to watch the exchange. The Police do this all the time, and it's especially helpful when you have an order of protection. You have an automatic witness to anything else he may want to try.
It keeps things calm and cool for the children, and then they don't have to fear coming home again.
It's not about winning and loosing, it's not about what's fair, or who owes who.... keep the focus about what is best for the Children, they are worth more than anything else.
Jeremiah 29:11 For I know the plans I have for you.........