It is going to depend on whether the estate assets consist of community property, separate property, or some sort of jointly held property. All community property passes to the surviving spouse. One-half of the separate property passes to your father’s children.
But I would also be a bit concerned that two years has now passed since your father’s death. You should speak with an attorney to make sure any claim you may have had has not expired due to the passage of time, and also discuss whether there really is any likelihood that there are assets that would pass to you and your sister.