I just need a copy of the extension form I filed in April

You need to use Print Center to get the Form 4868 extension request.

To access your current year online tax returns sign onto the TurboTax website with the User ID you used to create the account - https://myturbotax.intuit.com/

Click on Tax Tools on the left side of the online program screen.  Then click on Print Center.  Then click on Print, save or preview this year's return.  Choose the option Include government and TurboTax worksheets

You need to pay for your current year and then use print center to print your extension.