excessive child support

My wife, 2 boys and I lived in So. Calif.
In the Fall of 95, she left with the boys and moved to Sacramento. We were offically seperated in the spring of 96. then divorced in 98. In the summer of 99 she filed for an increase in child support and to collect the procedes from the sale of our house. During the meeting with our lawyers. Her lawyer proclaimed that I was inrears of child support. Which was false. My ex-wife even agreed. When they calculated the new support amount it calculated to 51% of my pay. Plus
I was to pay for Health insurance, and half of all Daycare, and half of all school supplies, and half of any recreational cost.
With with child support @ 51% plus the extras. The dollar amount totals up to aprox. 72% of my pay.
Is this normal? What does child support cover?

Just this month I had to take a transfer to Seattle to keep my career.

I want to take her back to court to have this re-evaluated. Also my boys now 12 and 10 yrs. old have expressed the disire to live with me .

I guess the heart of my question is: Since the all of the court proceedings have been in Sacramento. Do I have to file in Sacramento or can I file in Seattle. And would even be worth my expence and efforts to attempt this.

Last August my ex-wife filed for a increase in child support and to collect all the procedes from the sale of our former home.