Here is an organization that will be more then HAPPY to help you contact the school and stick up for you
http://www.aclj.org/
My Oldest Step, she was on the playground during recess having a friendly discussion with another child who believes about God an Easter. A yard duty teacher came up to her and told her she couldn't talk about that and if she continued she would be sent to the Office.
I called the people listed above and they were right on it!
That yard duty got talked to and we got an apology..
You have many rights don't let anyone tell you otherwise......