You can't include a previous year's 1099-R on the current year's tax return. If you need to add a 2015 1099-R then you'll have to file a 2015 amended return (1040X). You can do that thru TurboTax.
The IRS only accepts the 1040X on paper, so you'll have to print, sign, and mail it. Here's a link to the TurboTax support page for amending returns, which will get you started: https://turbotax.intuit.com/tax-tools/tax-tips/IRS-Tax-Return/Amending-Your-Income-Tax-Return/INF12058.html.
If you have a 2016 1099-R to include in the 2016 return you're working on, you'll enter it by clicking on the Federal Taxes tab, then Wages & Income, then scroll down to Retirement Plans & Social Security, and select IRA, 401(k), Pension Plan Withdrawals (1099-R). Then follow the prompts to enter your information.