Greenqueen is not correct.
As you are paying weekly maintenance above the Increase for a Qualified Child (IQA) rate - €29.80 a week. This is divided by 5 or 6 (depends if you are on Short Time Systematic or Casual work.
Have a look at the guidelines for increase for qualified children.
http://www.welfare.ie/EN/OperationalGuidelines/Pages/depsqc.aspx#normalres
Have a look at Section 4.
Hope this helps.