You don’t have to run Windows on your Mac; it’s much easier to buy TurboTax for Mac and transfer your return from your Windows PC to OS X. To run Windows on your Mac will require a copy of Windows and other software and that can be involved to install and run, so it’s cheaper and easier to buy TurboTax for the Mac.
Once you get a copy of TurboTax for the Mac and install it, transfer your Windows Turbotax files into TurboTax for the Mac. From your Windows PC, you’ll need to put them on a CD or a flash drive so the Mac can read it. (The flash drive can be Windows formatted and your Mac can still read it). Then on the Mac, import each year into a new return, save it and you’re done.
For more instructions, see this article at the TurboTax website: How do I transfer my tax return from Windows to Mac? – TurboTax Software Support.