I've got some advice just not sure how to word it so I will just offer up some hair tips instead
Products to buy/try:
Creme of Nature Detangling Shampoo
Mixed Chicks Leave in Conditioner
Moroccan Oil Intense Curl Cream
Wide tooth comb
If she has really dry hair don't use shampoo to cleanse instead use a cheap conditioner.
Take her to a black salon. Befriend a black American at the park and ask her questions. I'd happily talk hair with you and share the hang ups you do.not.want.to.pass.on to your beautiful little girl.
Play "Brown Skin" and "I Am Not My Hair" by India.Arie in the car and talk to her about how smart and beautiful she is.
Most importantly be gentle with you. Its hard to parent effectively when you add guilt in the mix. Come up with some zingers for strangers who lack tact.