Sibling rivalry help?

I have a 5-year-old daughter, a 3-year-old son and a 2-month-old son. My daughter is a very smart and responsible little 5 year old. All she wants to do is help and pretty much never gets into trouble. The one problem is her jealousy over my 2-month-old. Her and my 3-year-old are best buddies. They are always playing and laughing and are inseparable. She is always very fair and understanding with him, and also very protective. There was never any kind of problems when he was born and she was a proud 2-year-old big sister. She never liked the idea of another sibling. She made comments to me when I was pregnant about how she didn't want him, she never wanted to feel my belly, said she hated everything I bought for him. Now he is 2 months and she still gets mad when he cries, always wants to cuddle when I am feeding him, knowing I can't, and cries when I say I can't, complains when we have to go places with him, and so much more. My 3-year-old loves his brother, and she gets mad and jealous when he pays too much attention to him. I have tried spending as much time as possible with her and trying to get her to help and be involved with him but she has no interest. Any advice on what I can do to get her to like him more?