1. Assuming first marriage done as per Hindu rites and customs, you can file a petition in Court seeking divorce on grounds of S. 13 (1) (vi) HMA i.e. ‘has not been heard of as being alive for a period of seven years or more’. Here you have to hire an local advocate and via him file suit matter for divorce sending the Service of Summon Notice to your first husband’s last known address and via witnesses (your family side and friends) you may get divorce. Here your religious belief change in 2009 will not be treated as encumbrance as COI gives rights to Citizens to embrace religion of their choice (but change religion to get re-married is treated in different light which is mentioned in next para). However it may take 1-2 years (depending upon workload of Court) to get divorce under above suggested Section of The Act.
2. In a subsisting marriage when you changed religion without seeking divorce from your earlier marriage and got your-self re-married the second marriage (present one) is treated as not a valid marriage in eyes of Law or for any socio-practical purposes. Hence, no paper work should be submitted to any Authorities before your earlier marriage is dissolved by a competent Court least you fall into more socio-legal troubles later on.
3. Once you get proper decree in divorce from your first marriage proceed to get married under Special Marriage Act following the procedures where you need not have to change your adopted religion (Christianity), yet a already null and void marriage gets legal sanctity as being re-married in accordance with fulfilling procedures as per mention in Special Marriage Act.
4. Once you get divorce Decree and later a Marriage Registration Certificate of following marriage under Special Marriage Act submit both documents to Authorities and name change of first husband will be done in your passport and then following spouse sponsorship visa formalities of particular country your second husband will be able to take you / call you to rejoin him in overseas country is my view.
Observation: To follow para 1 and para 3 it will take long time say 1-3 years is my view, hence patience is required and suggested not to do more tricks in your personal life under influence of local advisory circle that you may keep. Reason being, I feel someone local guided you earlier to wait 7 years and get re-married and also guided you to change your religion after 7 years of wait to make second marriage authentic and due to following such faulty half backed legal advice you have come to this stage where neither from your first marriage you can find long term legal peace nor from your change of religion and then re-marriage there is any legal sanctity attached to such marriage. Without dissolving properly first marriage and then following para 3 you do not have any other legal solution in hand.