Let's consider the path you didn't take.
You have no earthly idea who owns the car that hit yours. So you snapped pictures of the car showing the damage and license plate, and took that to the cops, along with info of where the car tends to be parked. The cops decided how hot-n-heavy they wanted to get, and how exactly they wanted to take down this armed felon, if that's what he turned out to be.
Parallel to that, you also took this information to your insurance company, so they could send their adjuster out there and try to catch that car, and/or identify the owner and liase with that car's insurance company. This would have gotten your car fixed, obviously.
You did not choose that path, for reasons which are your own.
The path you did choose
Instead you chose to lay in wait, with an aim toward a confrontation. The problem with such things, is that they can go really sideways in a lot of unexpected ways. You know that, or reasonably should have known that.
And lucky you, it did go sideways in one of the more comical ways it could go, torn right out of a Jennifer Aniston movie about the workplace. Instead of one of the horrible ways it could go.
But as a result, your options are spent. Your actions had the effect of stalking your boss's boss, but not the intent and nothing more has come of this, so it can be dismissed as coincidence. You know the saying about odd misfortune:
Once is happenstance
Twice is coincidence
Three times is enemy action
This person is known to be cowardly, deceptive and manipulative. So if you press the matter further, she can be expected to try to disclaim the garage bump and use the weird garage encounter to twist your claim into an accusation against you.
Even if you now go to the police/insurance, she could claim you intentionally hit her so you could fabricate the claim as part of your stalking.
Have the courage to stick to your choice
The fact is, you decided that day to sit in your car and settle the matter with a confrontation instead of going via police or insurance. And let's be clear here: the police and insurance both want you handling inter-driver disputes through them precisely because driving incidents are so very personal and emotional. There's a very long history of people being swept away by their rage into true stupidity. The whole point of their services is to stop you from doing exactly what you did, which is get all torqued up about it and seek confrontation.
So you made your choice, confrontation instead of police/insurance. Now, you should sleep in the bed you made. You had your confrontation and it didn't go your way. Sometimes you get the bear, sometimes the bear gets you, doesn't make you a coward, just makes you a human. You have to swallow your pride and deal with it. That's part of picking fights, you lose about half the time.
Yes, I know it can itch at your brain. It feels like a lack of closure. That's just wounded pride. Losing a square fight, then jinking around looking for ways to re-fight it, (aka holding a grudge), that's the act of a coward. You made your choice, stay with it.