Fake birth certificate

I want to ask help about my problem about my daughters birth certificate. I have a 8 years old daughter who is born out of wedlock. She carries her biological fathers surename. We seperated less than a year after gaving birth to my daughter. With no comminication and support whatsoever.Then i met my husband and we wanted to change her surname to his.. so to cut the story short, we pay someone to do the job, only to find out after about 6 years that its fake. Unfortunately, the person who did it already passed. Now all her school records and baptismal are in my husbands surname(fake). She is now in 3rd grade and she doesnt know her biological father. What should i do. Please help.. we want to travel abroad but always hesitant because we cant take her with us. She also doesnt know anything about the situation and i want if possible that she will never find out about this. I dont know what to do now.