My question involves divorce in the State of: Texas

My child is 8 years old and she has her dad's last name. I am filing for divorce and want to change her name to my maiden last name. Her dad abandoned us on 6/11/10 and is now in Brazil. He will not come back. How can I request her name to be changed? Can my parents (her grandparents) co-petition the name change? Do I do this now, or just wait and add it to my Divorce Decree? Please help...