The only role model that such a young girl needs are her parents. Be the change you want to see in the world.
Read stories to her that paint women in a different light. Here are some suggestions:
1. The story of Gorgo, queen of Sparta and wife of Leonidas. Gorgo was probably the first documented woman cryptanalyst in the history of western civilization. Reference: Codebreakers.
2. A beautiful and educated woman named Hedy Lamarr invented spread-spectrum technology. We can thank her for modern wifi and cell phones. Reference: Spread Spectrum: Hedy Lamarr and the mobile phone
3. Amelia Earhart, a famous aviatrix and record setter: Who Was Amelia Earhart?
4. Jerri Mock, the first woman to fly solo around the world, . She did this in a single engine Cessna 180. Her autobiography has been recently re-released: Three-Eight Charlie: 1st Woman to Fly Solo Around the World
Read to her. Daily. Schedule at least 6 hours per week.
Limit her exposure to television. When she does watch television, explain to her that much of what is on television is sexist, unenlightened and designed to extract money from the mindless consumer masses. Be thankful that as a girl she isn't likely to descent into the life-sucking hell of video games, but limit (eliminate?) exposure to gaming anyway, for everyone in your house, parents and kids alike. Children cannot grow and flourish if a majority of their free time is spent manipulating pixels in synthetic worlds.
Have her choose a musical instrument. Buy a quality instrument that produces nice sounds. Hire a tutor. Take lessons with her if you don't already play an instrument.
As she gets a little older, buy educational toys for her, such as an electronics kit. You'll probably have to play with her yourself with such toys as other kids her age might not be interested.
Be the change you want to see in the world.