Its hard I know, my younger siblings in yr 2 had the same drama last yr. It even got to the stage when they were faking sickies just so they didnt have to see her! They were 6!!!
They go to a public school, and my mum didnt have any worries about approaching the school principal, and demand meetings to discuss the matter at hand!
Speaking up had worked, and continuing speaking up guarenteed they never had her as a teacher again.
They now have this teacher as a science teacher, and now makes a special effort to ensure they are enjoying her class.
I would say speak up, just cos' your child goes to that school gives you all the right as a parent to speak up on the welfare and education of your child.
I say go for it!