Is going through Child Support Enforcement in IL(Chicago) the only option to help someone collect child support?

Asked in Chicago, IL - 8 months

Divorced in 1/2009. My ex is supposed to be paying almost $600 every 2 weeks...I received 2 child support checks in 2009 and nothing since then. I haven't figured out the exact amount of $ he is behind in child support but the last time I did calculate it, it was over $50K. He moved out of the state 2 years ago and I know that he is in Ohio. I do know the city he is in but not the exact address. He is co-habitating with someone and has all bank accounts, etc put in her name so that nothing ever shows that he makes or has $. Am I able to collect child support if everything is in the girl's name that he lives with? He is the one who is supporting that household. What other options do I have to collect child support. My kids are 10 and 17 now. I have sole custody.