The Form 1099-R is correct. Enter the Form 1099-R exactly as received under Wages & Income -> Retirement Plans and Social Security -> IRA, 401(k), Pension Plan Withdrawals (1099-R), then answer the follow-up questions, indicating that you "did something else with the money," i.e., you did not roll it over to another Roth account.
Separately, enter your Roth IRA (MyRA) contribution for 2017 under Deductions & Credits -> Retirement and Investments -> Traditional and Roth IRA Contributions. (The MyRA was simply a special type of Roth IRA with limited investment options.)
TurboTax will use these amounts to prepare Form 8606 Part III to calculate the taxable amount of the distribution as the amount of the distribution minus your basis in Roth IRA contributions. The entire $2,612 will appear on Form 1040 line 15a or Form 1040A line 11a but only the taxable amount will appear on line 15b or 11b.
