The simple answer is that you need to contact an attorney.
It would seem that there are actions, such as failure to disclose residence, provide school information, allow visitation, that could be alleged in a contempt proceeding. There may also be an issue if she left state without securing court approval. If your assertions are proven, the Court, in a contempt setting, is empowered to not only have her pay your attorney's fees, but to invoke a jail sentence for non-compliance. There are other remedies, which could include a petition for custody.
Since the issues you raised do not appear to be able to resolve themselves, judicial intervention appears to be needed. That is the reason to secure the advise of an attorney. An experienced attorney in post-decree matters will be able to review your Judgment, consider your allegations/concerns, and suggest a plan of action to address the situation. Should this include locating your ex-wife and the children, that would be something else that the the attorney would need to address.
Answered on Jan 11th, 2012 at 3:05 PM