I am so sorry that you went through this. What a scary experience.
I agree that it was very good of you to try and help the girl out the way you did. I am sure she appreciated it.
As a suggestion call up one of the investigators at the Police Department and ask if they could do ocassional drive bys of your neighbourhood. They will not be able to assign someone to stay there but increased Police presence can be a deterent.
Stay safe but try not to let the incident make you crazy. Take precautions but don't let thaose bastards ruin your joy of living.
Also be sure not to get sucked in by well intentioned religionists who will likely try to use this opportunity to 'bring you closer to the Lord jesus". Zealots love to capitalize on tragedies.
Good luck and if you need to vent please do so. There are many good people here and they are always more than willing to listen.
Kismet