In most states she does not need an attorney to apply for modification of Child support, she just needs to file the appropriate papers with the Family Court. She needs to contact the court where the current support order is issued from and she can get the paperwork to file for an amendment, but will have to appear in court there.
Most states have a pretty cut and dried formula for figuring child support. For example, in NYS child support is 17% of the non custodial parents income for one child, 25% for two and so on. Other expenses are negtiable but child support is very clear.
GinnyG on Ravelry, I'd LOVE to be in your "friends"