Two wheeler driver hits four-wheeler but is demanding money

My father was driving a Santro Xing and was about to take the 4th exit in a roundabout. He was given green signal by the traffic police to drive and therefore he turned on the indicator and was driving towards the exit slowly. Now suddenly a Female two wheeler driver comes from behind and tries to overtake from the left side and hits left side of the front bumper and falls down. My father immediately hits brake and turns off the ignition. My father has all the updated documents and was wearing seatbelt while the lady did not wear any helmet. The present traffic police clicks photos of the accident and records the details. The traffic police even asked my father to go as he didnt have any fault. But my father insisted on taking the lady to the hospital out of sheer mankindness. Day after the accident, she calls us asking for money and forcing us to pay more. She is constantly calling us and threatening that she will send her brother to force us. She sent us picture of plastered leg. She threatened us to file a FIR against us. What are we supposed to do? It wasnt our fault and it is greatly unfair that we are being treated as such for the sole reason that we were driving a car and she was driving a scooty.