If you have already e-filed you can't change your payment method through TurboTax. However, you can call the IRS Payment Services at 1-888-353-4537 to inquire about your payment and request to change the payment method. You can also pay your Federal balance with your credit or debit card on their website.
Here's a link to the IRS website
for more information about payments: https://www.irs.gov/payments
