Get your taxes done using TurboTax

Do you mean that you should get a bigger deduction for your dependent ? The deduction is fixed per child.

The deduction will lower the amount that will be the base for your taxation. 

What make you think it is not more than you thought ?
The software will calculate the deduction for the dependent that you have so there is really nothing that you can do wrong as long as you enter the data for the child correctly.