How can my husbands ex-wife get more child support when she doesn't work or try to work?

They have two children together and now she is remarried with two more children. Neither her or her husband work and they are perfectly capable. They live off the system and child support from my husband. Recently she has been arrested for deception to obtain dangerous drugs, ovi, child endg. We have talked to a lawyer to get custody but were told that we probabaly wouldn't get it (wonderful ohio laws) however now she is trying to raise child support. Why is it that my husband is expected to and is happy to provide for his children but she doesn't have to? If a non-custodial parent chooses not to provide there are laws against that but the custodial parent doesn't have to contribute anything except filling out some paperwork to receive more $ either in support or from the system. We are infuriated that we are supporting the whole household (ex-wife, new husband, and all four kids) when only two kids are my husbands. She gets $900 a month and now wants more. My husband is a hardworker and has had his job for 13 years. This just does not seem right. Does anyone have any ideas on what we can do to change this