1. Power of Attorney has to be got attested from the Indian consulate in the country where he is residing. Unless and until the power of attorney is attested it cannot be used in court for filing the case. It takes not more than 20 minutes to get it attested from the consulate once the prior appointment has been obtained.
2. If he is not willing to lend you his cooperation in getting divorce then you may unilaterally file for divorce without waiting any further for him to cooperate.
3. You cannot remarry unless and until you are divorced. Change of religion also does not permit one to remarry. There is no alternative to a legal termination of marriage characterized by a divorce granted by court.
4. As per the facts furnished by you, you lived with your husband for merely 4 days after marriage, and more than a year has seemingly passed. In such a scenario an action for annulment will not survive in court.