How do I bring my wife back if our marriage was unknown to our family?

I have a girlfriend since November 2011 and we are in deep love since last the 5 years. After that, we got marriage in May 2013. We didn't do any marriage registration for that marriage. We didn't tell about our marriage to anybody. At that time, she is stayed in a hostel which is near to my house for her studies. At that time, she is a major also. From the beginning of my love, we are maintaining physical relationship also. We regularly meet in various hotels. In September 2013, she got pregnant. She forced me to do an abortion but I am not interested. Finally, she convinced me to do the abortion because of her unmarried elder sister's marriage and her future life. In December 2013, I did the abortion and I lost my 18 week baby boy. After that, we both are staying in in residential apartment, living together for the purpose of jobs since January 2015 to September 2015. My brother’s son is also staying with me in my flat and her sister was also staying for a month in September 2015. Their parents think my relationship is only friendship. After that, we both are coming to my home town because of our job changes. I am living with my parents and I joined my wife in a hostel near to my hometown. Her village is 450 km. away to my town. We both are lived very happily together since June 2016. In that month, she resigned from her job because of the pressure and gone to her home town. In the last month, we both are revealed about our relationship in our houses. My parents accepted my relationship but her parents did not. I also used to convey her mother and sister by phone but they didn't accept my relationship and they are speaking very rudely and scolded me and they showed the reason of caste differences. Here what I am shocked as my wife also convinced by her parents and she is also not telling to her parents about our marriage. Now, she is living with her parents.