Stalker is taking pictures without parents permission, illegal?

i have this lady that has been stalking my children and i for over 5 yrs. she daughter gose to the same public school as my two young boys. she insists on posting horrable comments on FB and ive told here to leave us all alone or else i would go to the athourities. she commented on my youngest pictures that my mom has posted and i told her tha she was lucky to even have seen it and that she should keep her thoughts to her self....now im sure this might sound petty but this has been an ongoing sistuation for a few years now. the problem is, is that she pulled my oldest off the jungle gym to have him take pictures with her daughter. now keep in mind that i have repeatedly told this woman not to talk or approach my children in any shape or form....what should i do?