need advice

[spinmaster61]

Florida
I filed for child support a year ago. We were divorced in Jan 2003. My daughter stayed with me for 6 months after the divorce in 2003 then went with her mother to live in Oklahoma. She came back June 5, 2005. To stay with me permantley. She went to spend the summer vacation of 2007 in Ok. and I had to get her back thru the court system because her mother decided to take her to DHS and give her to the state so that she would not have to pay child support. So she thought.
In the fall of 2007 I file to get help thru the Dept. of Revenue to get child support. Because now I am disabled and the Mother can afford to pay support and doesn't support the daughter or the son either as a matter of fact. The Dept. went after her for contempt for $27,000. Because they were going with the original maritial agreement but that should not have included the two yrs that the daughter was with her. So the Dept. had to change the motion to a motion to clarify final judgement instead of contempt. At the hearing all the judge did was say that the whole maritial agreement was null and void, and didn't clarify anything. The judge asked if the money was for the state or for me and the attorney stated that the money was not for the state. At that time I told the court that I only wanted support from 2005 in all fairness. Because it was when she came home. At that hearing the judge did nothing at all except say that it was null and void but did not award any child support.
Since this hearing her attorney has rewritten the maritial agreement so that she would only start paying support in March 2008 instead of June 2005 that way she could get out of having to pay back support. Which is not fair to me or the child.

Question:
1. How can he null & void this after the judge in 2003 granted the divorce?
2. Can I go back to 2005 for child support?
3. Should I ask the Lawyer who did the divorce to fix his mess or was it my fault?
4. Should the Laywer that did the divorce fix this for free?
5. My son is 20 he is a disable adult child can I get back support for him also?
6. Is there any action legally against the judge who did the divorce in 2003?