F.R.
I really suggest that you find things to do that involve all of you, even daddy. She must learn that the world doesn't revolve around her, but that there is other members that need just as much attention. (not saying you shouldn't find quality time with her alone) If income is limited, find activites that involve everyone, park trips, indoor hide and seek, or rewards to her when she helps out with the twins. A trip to her favorite movie, or lunch at her favorite place to eat but get her involved with helping out taking care of the twin. She needs some quality time in helping within the family. Maybe Dad could use some help in the garage, yard, or take along to his job one day. Get her out of her room and involved.