A modification of an order requires a substantial change in circumstances which is unanticipated. If you have a significant increase in pay, (without knowing anything else) it likely meets the substantial change requirement. Typically the child care expenses are included into the child support calculation. However, if your current order clearly states that you will each be responsible for your own, then typically that would stay the same. She will attempt to argue that the child care amount is part of the calculation and you should be responsible. You can include your cost of child care in your calculations and see how much it changes. You should speak to a lawyer that can run a child support calculation and see what sort of difference you are looking at.
This answer is provided for a general purpose, as I am not privvy to all the details or documents relating to your case. This answer does not establish an attorney-client relationship. Prior to taking any action, you should consult with an attorney who has the opportunity to learn all the factors of your case or situation.