Assalāmu `alaikum Warahmatullāhi Wabrakatuh,
There are many people who are stuck in life and do not know how to proceed. They feel ashamed of their condition and do not discuss their issues with anyone. They remain stuck in that condition. Allah Taala guided you to seek guidance. This is tawfeeq from Allah Taala. He wishes to guide you and bless you with hidayat. It is also encouraging to note that you have become conscious of Deen recently. It is the barakah and blessing of this consciousness that you are seeking Deeni counsel on your issue. May Allah Taala keep you steadfast in Deen. Aameen.
You did not state to us how the marriage was registered in the country of the girl for us to determine the Shari legitimacy of the marriage. Nevertheless, our advice to you is if the girl is sincere in accepting Islam and there are all indications of her wanting to be a Muslim, you should strongly consider her request to go over to her, especially since you too have inclinations towards her. Make it very clear to her that you are a conscious Muslim and you will not compromise on your Islamic values. If she accepts Islam, perform Nikah and live with her. That will give you the opportunity to be with your biological son and raise him with Islamic values.
If the girl cannot openly practice Islam in front of her parents, tolerate that. When she lives with you in your country, you could make an effort on her and build her confidence and strength in Ieman. As time goes by, conditions change and circumstances change. She may deal with her parents accordingly.
And Allah Ta'āla Knows Best,
Muftī Ebrahim Desai
Daruliftaa
35 Candella Rd, Durban, South Africa