The young Matangi woman, who had tried to seek help a week before the fatal accident for drug and alcohol problems, stood in the dock sobbing silently during the sentencing.
She was supported by her parents, other family members, friends and acquaintances she had met at the Wings Trust Higher Ground drug and alcohol rehabilitation programme.
Mrs Hepburn's family filled the back row of the courtroom.
Storey read a statement to the court saying that her "world dissolved around her" when she learned of the tragedy as she had no memory of the accident.
"Every fibre of my body was screaming it couldn't possibly be true," she said through tears.
"I have taken a mother away from her child, a grandmother away from her grandchild, a neighbour away from her friend, a wife away from her husband.
"I destroyed my life, I'm constantly reminded of this every time I close my eyes and I hear sirens down the street haunting me every step I take.
"I can't change what happened but I promise you I will do anything to make sure it never happens again. Even if it means I go to jail, or that I never get behind the wheel of a car again or that I go out into the community and share my experience with others ... I will do anything to keep that promise to you."
She also thanked Mrs Hepburn's husband, Bill Hepburn, for his forgiveness, support and understanding and said that without it the accident would have taken two lives.
Mr Hepburn's "remarkable" forgiveness was also referred to by the judge, Storey's lawyer, Louis Wilkins, and the Crown prosecutor, Senior Constable Steven Bell.
Mr Hepburn said being a Jehovah's Witness had taught him to forgive and he hoped something good could come from the tragedy - even if just one person read about Storey and decided to get help for drug and alcohol problems before it was too late.