the first thing you do is hire a lawyer.
it is always difficult to determine the real income of a self employed person.
there are five appellate court cases that say in cases of fluctuating income, average the last three years income and use that to set support.
it is too late in this year to set supt based on last year if his income now is greater than all of 2012.
hire a lawyer.
You really should hire a divorce lawyer. There are different avenues that lawyers use to try to determine the income of a self-employed person. These methods are impossible to explain in this Q & A forum.