What can I do?

I hv been staying in Russia for 18yrs.got to know that my husband was involved with my house maid,she has 2children,1from her previous owner ,n the other from my husband.she being a single woman ,has right to change her family name to any name,but of a particular person ,she has to take his written permission,or until the courts decision takes place.as soon as her second child was born,she registered,him in the act of marriage,and using her right of a single woman ,she changed her family name first and then added the fathers name ,so that the child has the fathers paternity ,whether,it is established or not.then ,she also changed her older sons name to my husbands,paternity.so that she now looks like his family.a court proceeding was on,and my husband has to pay maintain ace ,for only the younger child.my husband n me hv 2 daughters ,and ,this projection of family is stressing us tremendously,how can we prove that she has misused her right.?she is causing us social damage,and also my husband does not know how to prove that he has not signed any where yet ,she has in legal documents ,put child in the act of marriage .we hv cleared that the older child is not the biological child,yet his passport and birthcertificate show my husband as his father.we don't want her to be connected to our family nor shud she look a part of our family.socially and for us to try n stay as a family again is getting v hard coz of this.please do find a way out.thank you.