L.M.
N.,
I have a 5 year old boy and a 3 year old girl. Like you, I work full-time. I was going crazy with the same problem and wanted both kids to feel special. A few months ago, I started having what I call "girl time." Sometimes, we will go have some hot chocolate together, she can help with making dinner, paint nails, or just take her to the grocery store...anything where she has my full attention without having to compete with her older brother. She absolutely loves it and often says, "Mom, it's just the girls."
Good luck!
L.