Dear Be_Yourself~
Welcome \ here to the Forum, a good place to come to see other people's experiences. It is only natuarl you should want your children to see your country and their heritage.
Custody is a complicated matter and it is difficult to take children interstate, I would think taking them out of the country would be even more problematic. It does not sound from what you say your ex is in favor of this.
The only suggestion I have concerning legal advice is the Women's Legal Service, which has branches in most states, that link takes you to the directory.
I hope you find someone to help.
Croix
