Since the child is small so its difficult for her to settle down n get her treatment done, so its advised to take her to a PEDODONTIST (child specialist in dentistry) he/she can guide you what is better for your child. Generally if 1/3rd of a tooth is broken then it can be repaired with a filling, but if more than 1/3rd is gone then Root Canal is mandatory followed by capping. It's necessary to preserve these teeth till the permanent one's arrive as these act as a guiding path for the permanent one's.
Next Steps
Visit a pedodontist and try to restore them with filling or RCT and capping.
Health Tips
Do not go for extraction until the teeth are mobile.