OMG, she is clearly deranged. There is no such thing as a customary one month bonus. Bonuses are given at the discretion of the employer for excellent work. Bonuses are not demanded by employees. Do not answer her calls anymore---ever. If you have never read "The Gift of Fear" by Gavin DeBecker, now might be a good time to pick up a copy.
In "The Gift of Fear," I believe, there was a discussion of how to respond to harassment like that. A common response is to threaten to call the police/get a restraining order. The author argued that that this kind of thing can actually escalate matters, and that one should instead cease all contact. The author strongly encourages people to be alert for signs of danger. If you have not read the book yet, this would be a good time to do so.
Absolutely agree with changing the daycare consent. Make sure everyone at the daycare understands the situation and does not allow her any contact with your children whatsoever.