You can amend them using TurboTax but it is difficult since your return was not originally prepared using TurboTax. Why not have the accountant do it?
You would need to buy and download the 2017 TurboTax product and install it on your computer. You would then have to prepare a tax return to match exactly the tax return that you originally filed. After you have completed it and verified that it matches the filed return exactly, you can then begin to amend it.