Legal issue for divorce

My name is Sharebanu and I am married to a guy who is from Hyderabad and since last 12 years he is living in Saudi Arabia. After 11 years of marriage I stayed with him in Saudi for 3 years and then returned back to my in-laws house in Hyderabad. I have 2 sons of age 10 and 11 years. 2 years back due to unavoidable issues at home, I left my inl-aws house with 2 kids and came back to my parents. The incidents of harassment happened in Hyderabad. There when we went to police, they told us to file the case in Ahmedabad. We did that. After 2 years we have received a letter from Hyderabad lawyer about this matter and the information mentioned in that letter is not true. So now I want to know that if I want to reply to this letter, should I do the case filing here in Ahmedabad or do I have to visit the place where the incident happened in order to file case. All my belongings are still at my in-laws place. I also want to know how much time this matter would get to resolve as I am planning to move outside India with children for better future. Will I need the NOC from my husband to travel with children outside India? Do I have the right to travel outside country and stay as an immigrant if divorce is not filed? As I believe this process would take a lot of time. Please guide me for this.