Though legally, at least in Ontario, hitting someone from behind means an automatic fault, any cyclist knows this kind of situation all too well. Somebody speeds past you, cuts in front of you, and hits the breaks (often to turn, obstructing even more of the lane). Happens to me nearly every day. It's bull*****, really dangerous (though seldom for the people in the car) and rarely saves any driver more than 6 seconds. Unfortunately cars tend to give people an instant ego boost, a Formula 1 complex and a huge decrease in visibility. To further complicate matters, most people around here seem to assume a fixed speed of 15-20 km/h (about as fast as they can go with their Huffy MTB with low tire pressure and a rusty chain) for every bike they see, regardless of what their eyes tell them, causing them to preform all manner of dangerous manoeuvres in front of them thinking they've got time.

That said, I very rarely hit people from behind, because I'm cautious, ride with a break, and have a keen sense for when somebody's going to do something stupid.

You F%#$ed up her car. Probably cost hundreds to fix, at least. And didn't get hurt.

In short, you won.