If the facts are as they appear to be, you can do what you intend to do where you are. In the U.S., under the "UCCJEA," Canada retains "exclusive modification jurisdiction" so long as a party to the original custody order remains in the place that issued it. So you may be able to start a custody modification case in Ontario. Consult local counsel as soon as possible.
Additionally, while your facts are a bit sketchy, you might be able to pursue a claim for recovery of the child and return to Canada through the Hague Convention. THis requires that you have "rights of custody" under the prior orders and that the child was "wrongfully removed" or "wrongfully retained" preventing you from exercising those rights. On your facts, I cannot tell.
For some background materials describing all of this, see the explanations and materials posted on the child custody page of our firm website:
http://willicklawgroup.com/child-custody-and-visitation/. But be aware that there are time limits to most things you can do under the law, so consult with counsel, and then act quickly.
Answered on Feb 21st, 2014 at 10:41 AM