There is a lot of conflicting info here, so I'll chime in with my experience. First you don't say that you were married, so I'll assume you weren't, you simply bought a home together. If you have comfortably dealt with the house issue, as well as any other joint debt, then there really isn't a need for an attorney and court.
Child support is normally done, when custody papers and divorce papers aren't needed, through the child support agency. they create the court order and you may have to appear once or twice, but it really is J. a matter of them collecting the employment information and the cost of child care. They do NOT care about outside debt, unless it is other children, or support orders.
this does mean that a child support order is NOT always fair. I know lots of good dad's who see their kids and pay their support and can't afford to live alone, or own a car ect. because of what they pay in support after their others bills are paid. Child support is factored off an income percentage, a gross income percentage, not spendable income.
It is also completely possible to come to an agreement, get 1 attorney, who will only represent one of you, but can draw up the papers, go before a judge and basically say this is what we want and why and have it work. My ex husband and I did exactly that, and child support was determined at a rate that i was ok with and that was lower than normal because he provides clothing and pays for activities ect. things that i normally would have to pay by normal state laws.
You obviously know what he makes, and know some of his debt, take a good long look at how much of that debt was shared and that he agreed to take over, is he still paying for the house until it sells or are you paying part? go tot he court house and get a copy of a standard visitation order, and see all the things that YOU as a custodial parent are responsible for, such as clothing your child while with dad, and see if he does any of those things and factor in that cost. And don't forget insurance, does he insure her? I used our local calculator and got about 900 as well, but that does not factor in insurance or other support that he may be paying.
But those are J. things to think about to maybe keep the peace. good luck.