Am I Paying Too Much In Child Support

I make 15 dollars an hour and after taxes my checks are usually 486/week. Each week $177 is taken out of the 486. So, my checks are around $309. Here are my Bills. I live in the state of Kansas.Rent - $350/month, Car Payment - $408/month
Insurance - $130/month, Electric - $150/month avg.
Gas Company - $125/month avg.Phone - $50/month.

These are just my minimal bills. I am not including anything else at all, not food, gas for my vehicle, toiletries or anything else. My fiance lives with me now and she doesn't work because we are about to have twins in less than a month and she can't work. So, I am bringing in the only income. I just don't understand why I was ordered to pay so much when I don't make enough to even pay my own bill's. Plus, I'm about to have two more babies. Please help. Who do I call, what do I do? I have no money what so ever and I can't afford a lawyer. Is there any pro bono work out there?