My wife and I are different Nationalities. We got married in her country about 2 years ago, we have recently moved and now reside in my country of origin (within Africa). Does anybody know if its possible for us to get divorced in my country or would we have to return to her country to finalise? We have two children, born in my country, what are the chances of them staying with me?

If she now becomes lawful permanent resident in your country, it means your marriage has
Been acknowledged by immigration process and you can file for divorce in your country.

The chance to get child custody depends on family court... I am not familiar with the law in
Your country but normally if she is not an unfit mother, then you might have to share custody.