TurboTax isn't set up to process credit card payments for state returns as most states require you to make the payment using their systems and some have limited credit card payment options. You would select pay tax by check and then go to your state's website to pay your taxes by credit card using the amount due shown on your forms.
If you want to let me know what state you are in, I can provide you with a link to the credit card payment option for your state or you can probably easily find it using an internet search.
