Doctor left sponge during cesarean delivery

Hi all respected lawyers, i would like to share a case which is very rare and thats why i have no idea where to start to get justice.. my wife delivery done through cesarean process on 6th january 2017,she suffered endless pain after surgery in her stomach..after 15 days of pain i thought to take her to a medical college trauma centre,she got admitted and CT abdomen done on 27 jan 2017,CT clearly said that there is a foreign body which causes intestine obstruction and perforation,damage was already done..Doctors told me to operate her next day on 28th jan 2017.. operation done and she taken to ICU for two days..Doctors done Ileostomy and after more than two months she is suffering with life..next week she will be operated again to connect both intestine.. she is currently under treatment.. i dont get time to think or file a case or do anything against the doctor or hospital..till date i also not shared anything to anyone..my first objective is her wellness as soon as possible.. doctors who take out sponge not mentioned anything in discharge slip that she had a foreign body..when i asked why they cant mention the same they told me that this is the rule of medical college and they cant giv me in written..they also taken all reports during operation..i dont have enough evidence to prove anything but they told me also that i can file a RTI and get information for everything..with proper channel i can get the case reports.. I wanted two things to know.. First is can i file case later as i dnt hav time right now for handling anything.. Second is what i can do best to get justice and how much compensation can be made..i wanted the doctor who left sponge to be hanged..he made life hell of us