Extortion usually requires the demand for money or some other pecuniary interest and the threat is most often physical harm to you or your family. You'd have to speak with a criminal attorney in your local area about the definitions of the various criminal acts.
Also, if she is in another state, there will be issues raised about where she can be charged.
By responding to questions on AVVO does not establish an attorney-client relationship between the questioner and Garrett Law Group, PLC. Responses should be considered and used for informational purposes only. Every case is unique in its facts, and all legal matters should be discussed with a licensed attorney prior to making any decisions or taking any actions.
Consider consulting a domestic relations attorney - might be able to send a letter to cease her behavior - or possibly obtain a restraining order.
This is not intended to be legal advise or as legal representation. I am a California personal injury attorney . Be aware that every state has its own statute of limitations; and statutes & case laws that govern the handling of these matters.