I am being harassed by a police officer, need help and advice

Hello Sir, On 14th Jan, 2006 in there was a party in my Building Society, I got drunked majorly and after that a family quarrel happened. My Mother In Law was also there at my place. My wife then called 100 Police support and I was picked from my home. I stayed the complete night in police custody until morning when my wife and my mother-in-law came to the station. They lodged an FIR, and after mutual discussion they then requested the police to withdraw the FIR, the police person said that once FIR is lodged, it can't be withdrawn as it has to go to PI Court. SO the police ultimately told that I have to pay them 30000 so that they can make some arrangements and withdraw the case. My Wife and in law then payed 25000 and did a medical test and I was released, on a condition that they will call me for further investigation. Now the police man wants the remaining money from me and he is saying that the under 41A I have to appear infront of them as the offence is cognisable offence and 498A, which I don't understand. I told him that since the case was sent to PI court, we will go to PI and my wife and Mother in Law will release the case, however the police man said that I have to go to police station and sign some bond, which again I don't understand, so Kindly suggest me what should I do and what is happening...