If a DNA test shows someone is a child's dad, the test doesn't enable the dad to just walk in and lay out the terms and conditions regarding custody or anything else. It becomes a discussion for your attorney and his attorney, and visitation terms (or shared custody) and child support payments are worked out by the lawyers and approved by the judge. There are standard amounts of child support that the non-custodial parent pays the custodial parent, based on how much the non-custodial parent earns.
Be clear, this is not not not NOT something for you and the dad to try to work out on your own. If you've gone so far as a DNA test and now you think somehow that "gives him any type of custody," you need a lawyer like yesterday. Don't sign anything, don't sit down with him to try to work it out because you don't want to have to pay for legal help. Talk to a lawyer or someone at a legal aid clinic, and move now.