I know how you feel. My mom had just picked up her brand new 3 series and we were taking it for a drive (to show the family etc) and we stopped and this lady in front of us obviously didnt see us behind and while waiting to cross a busy main road her car started coming backwards towards ours and my mom hooted and screamed but the BMW hooter is useless and so muffled the lady heard nothing and kept coming.
My dad ordered my mom to reverse but being reasonable late in the afternoon the sun was shining through the back of the car. So my mom was too scared to reverse cos she could not see behind us.
Basically she floored the car and pulled out from behind the stupid woman and my dad got out and still her car was rolling backwards and after hitting her window she finally like woke up and realised she aint the only person around. But I know how you feel, seeing something about to happen and you cant stop it. Fortunatly with our BMW we had the luck of pulling out. All of this happened in the space of ten seconds.
We also had out Mitsubishi Pajero stoned by a bunch of teenagers and I know how depressed my dad was after that cos the Pajero is his pride and joy. So much so that the went back the following night and using a SLR Camera he photographed the teens and managed to get the parents (who were all extremely wealthy) to pay the damages at the best bodyshop in Cape Town.
We have had bad luck with cars. Even when my ma wrote off two 18" Monza rims. But the point is that cars are so dangerous and I know its upsetting but rather be happy she didnt hit you at 100Km per hour or 80miles and do damage to your family. Its a car. Even if you love it more than your wife. It can always be repaired.
I should become a counsellor.....

Mike