Can the custodial parent be charged with fraud for lying on the court documents stating her expenses and income? She has listed that she pays daycare for a 12 year old that babysits her other children to a family member. Also I believe the amount she listed to her new husbands income is lower than it really is. Is there any way to take this back to court and make her prove this?

Sure - anyone can be prosecuted for lying to court. Its called perjury and it's a felony.

Generally, in such cases there is a requirement to produce documentation of income; pay stubs, tax returns, etc. If no documents were produced why didn't you ask for them?

As for the babysitter, that will be hard to prove false.

But, as Steve said, lying in court is perjury. But you need to prove it before the state will prosecute.