Please U-turn carefully

This incident happened this morning and made me boil when i think of it.
I was on my way to a course at Sims Ave...happily driving along. I was coming down a straight road, and 2 lanes merged into 1. Of course, there's a 3rd lane to my right. So, imagine the picture. Ahead of me is 3 lanes, of which 2 are merging lanes, and I was travelling along the left most of the merging lanes.
THENNNNNNNN.....this driver had to make a u-turn. Where ? On the oppsite side of the road. U-turn to where ? Onto my side of the road. Is it a good U-turn ? NOOOOO ! She made such a wide turn that she cut into my lane that I was travelling on ! And what made me mad is the fact that I was coming down fast, and she should have better judgement not to turn till i've passed.
That's not the end. I did an emergency brake, and by the time my car stopped fully, and by the time she had made her slow and dangerous u-turn, we nearly hit. I was soooooooo pissed. I horned many many many times, flashed at her many many times, and from the mirror, she made some hand signals at me.
Was i one to be trifled with ? Of course not. I drove right up to her, pulled beside her, and gave her double.
What a way to start my day.