Going to court to modify a child support order how do I get what I need?

I opened a child support case in 1998 and we are now modifying it for the first time. I have custody of my son, his biological father has never seen him. I have called him several times because my son would like to meet him but we have had no luck. He left when I was pregnant and has never met him. However, he lives 30 min away. Now that we are going back to court I need to provide proof that he is married. They even asked if I had a wedding invitation. I obviously don't. How can I get proof. He was sent paper but did not send them back. They don't even have his current wage info. They used his wages from 2006 -2007. By the way he is a Paramedic. I am currently a stay at home mom. I actually home school my son because we found out about 2 1/2 yrs ago that he was Dyslexic. So I am home with him trying to help him catch up to his grade level. Right now my fiance is supporting us. Any ideas on how to get this done would be greatly appreciated.