Cheque bounce nd signature mismatch

My wife working in AIIMS helped her friend for her marriage before 2 years.. She gave her 35000/- for a condition to give it back with in two month without any interest. The borrower also a staff in AIIMS .We asked her about this money many times and she used to tell excuses. After one and half year One day me and one of my friend went to her shop and asked to her husband about this money and that time they have provided a cheque of Rs. 35000.. And I deposited that cheque into bank and that has got bounced because of insufficient balance and signature mismatch.. Then the borrower done a transaction of Rs 2000 in the month of July and 5000 in the month of august to my wife's account. And now she is not willing to pay the remaining amount How can I go legally to file a complaint against her. The borrower told me that she paid this much amount against as her cheque and will pay the remaining money later. I am sure that she is not going to pay me the remaining amount ..we have waited 2 year for getting our money back .. What should we do now?