If my dad died December 2015 my sister took everything, what can I do to get what is rightfully mine? She is my dad's step daughter.

She cleared the house the garage took all vehicles and is renting his house out. She refuses to send me copies of the inventory list his will she has sold many things and says there is no money. She is executor and my dad's step daughter. She lied to me about my dad's sickness lied to me about how long he had to live. She has rented his house out. She said the will states half between her and I. I have my dad's family to back up that he would not have done that and if he had he was sick and didn't know what he was doing. She will not let me in his house and she is driving his vehicles and I need to know what rights I have and what I can do to get what is rightfully mine. There is more things that happened while he was dying at home and I was there taking care of him while she and her son's cleared out his gun cabinets the safe with cash and other things before he was even dead. Right after he died she kicked me out of his house and has not allowed me there since.