Parallels is a good solution if you want to be able to run your Windows software at the same time as other Mac applications.
Another solution would be Boot Camp, which reboots the entire Mac into Windows, but the disadvantage is that no Mac programs can be run since it makes the entire Mac work like a Windows PC.
Before you buy Parallels, you might consider similar alternatives. A competitor to Parallels is VMWare Fusion, and another alternative is VirtualBox which is free.
But whichever alternative you pick, you will need a legitimate Windows license to be able to install Windows. All those products to is allow you to run Windows, but they don't include Windows itself (unless they say they do).