I don't trust the mother of my child with money and don't believe the money will go towards my baby. If I go down to the offices myself and request to be put on child support, would I be paying more or less?

That depends upon the income calculations. If you start the process you have the advantage of not being surprised by any sanctions imposed by the courts for failure of nonpayment. The agency is only responsible for collecting the funds not how she spends the money.

It depends on how much you're paying now, her and your income and the expenses of the baby. There are free child support calculators online to guesstimate what you'd pay. But unfortunately unless it is very obvious she is not taking care of the child, no one can dictate what she uses the support on. Rent, utilities, gas, car payment, day care, food, clothes for her (with in reason like for work) all are considered needs of the baby.