Right for share in father property

Good Morning Sir, My Parents were dead in the year 2003.(mother died 10 months before father) we are 6 brothers and 2 sisters. i am the 3rd son. My father has a land of 1600 sq yards. In the same land we have a house in about 200 sq yards. Our matter is a bit complicated, let me explain it step by step. 1.Before my father death, in 1995 he gifted this house(only house) to my mother.This gift was signed only on stamp paper,but not registered with government. 2.Also in the same stamp paper, he distributed some open land to my 3 younger brothers.(how much area they get is not mentioned in it). 3.He also mentioned in that paper that, each of my daughters will get 121 yards individually. There is no distribution of property for the elder 3 brothers. But my 2nd elder brother constructed a house in that land in around 200 yards and staying in it. Now there is a dispute between all of us. Me and My elder brother are not to take share in that property. Can you please guide me how to get my share in my father property.And also please tell me how much share should i get or my brothers should get. And most important, is that stamp paper valid ? does it have effect, because still the property is on my Late Fathers Name. Also about the house gifted to my mother, as she died before my father. it was also not registered. please explain me to your best. Thanks & Regards Ahmed