Property dispute among three brother

I have two brothers, one elder and one younger and one sister. My age is 50, age of elder brother is 55 and that of younger is 48. My sister is no more, she was married and had a happy family. we have around 40 acres of land. The property is not yet distributed legally. Elder brother had acquired land a lot more than one third of total property from past 10 years and also sold some part of it without permission from other two brother. Now following the trend, younger brother also started selling some part of property without any approval of others. when I demand for proper or legal distribution, both start a quarrel, abusing and also threaten me. The family of my sister is not interested in that property any more. I also talked to some relative but my brothers are not ready to listen any one of them. Please guide me what to do? If I file a suit for partition, will I get one third of whole 40 acres or just one third of remaining unsold property? If family of my sister is not interested in whole property, then how the partition will happen?