You need to file a partition suit in civil court for partion of property and your share If there is no will on record.

You all siblings that you ,your brother step sisters and the step.mother shall have equal share in the property.

On demise of father you have one fourth share in property 

2) you can file suit for partition for division of property by metes and bounds 

3) seek injunction restraining sale of property by step mother and step sister 

See either you can start leaving separetly or you can mutually settle with mother. Further you and your wife can also complaint before the police or directly with magistrate that for property she is intimidating for false.cases and filing false complaint.

You can file partition suit as advised herein above 

you have equal share in property and cannot be thrown out of house 

record all abuses  of step mother . It would help you in making out case against step mother 

After father died property will be divided equally into all legal heir class1. 

You can file partition suit in jurisdiction civil court. 

1. It is not clear whether your father has left any Will in favour of your step mother or step siblings or not.

2. If no then no death of your father all f you have equal share with them in undivided 1/4th share in his properties.

3. Since they are not giving you the due share, you can file a suit for partition to claim your respective 1/4th share and injunction so the property can not be sold in the meantime.

If your mother is not giving you the share in the property then you have to approach to the Civil Court to get your share in the property the property of your father will be divided into four part two parts for two brothers and one part for sister and one part for the mother means all the legal hairs will have the same share in the property you need to try to maintain the balance in the family so that your mother should not run to the police station because this is going to create unnecessary problems for you as your mother is a stepmother just go legally to get your hair from the court

1) You and your sister has 50% share in your father's property.

The property belongs to your father and was a self acquired property therefore belongs to you your siblings and your step mother and her children.

Regards 

Step mother and sister cannot claim exclusive right as you and your sister have equal right in your father's property 

You need to file a partition suit to claim your and your sister's share 

File an interim application against your step mom and sister in above suit to injuct them from selling the property till partition suit is decided

1. If your father died intestate i.e without making a will then his property has devolved through intestate succession on his Class 1 heirs i.e his widow and children.

2. If your step sister is the biological child of your father then she too gets a share in the property of her father, else the property has devolved on you, your sister and step mother in the share of 1/3rd each.

3. You and your sister are at liberty to file a suit for partition to cull out your shares in the property. Also seek injunction to stop them from creating third party rights in the property during the pendency of the suit.

You can file for the partition suit in court. The court will divide the same as per the legal share of class 1 heir