How can a Canadian citizen Father take custody of his child where mother is with kids in the USA?

Hi I am Canadian, I married an american women and have a daughter, I am about to undergo a divorcing process both my ex and we have both lost jobs. I have better chances of getting a new job in canada. should i file from canada or from colorado? …what are the chances if my daughter is in colorado that i can get the child custody if i am in Canada? what can i do? does it mark a difference if my soon ex has bipolar issues and pot dependency?

Drug use and mental illness are always factors the court considers when granting custody, you can file in either country and once the custody is granted US authorities will turn your child over to you based upon the order whichever court orders it.~