you don't need to buy any special program. Just buy windows 7 and install it on the mac. All new mac OS have a capability called BOOTCAMP. This will allow you to install windows on a different partition. It is very user friendly and straight forward installation. Every time you start your Mac a window will appear and ask you if you want load windows or Mac OS.
In this way your Mac will work exactly like a normal PC.
Programs like parallels etc are EMULATORS that are only needed if you wish to run windows program or applications inside the Mac OSx environment which is totally unnecessary. In your case you just need to have the dual boot option (BOOTCAMP), which is free.
