Hi,
You can download games from the iTunes Store solely for Apple iOS devices such as the iPad, iPhone and iPod.
You can download similar, if not the same games, for Apple Macintosh computers from the Apple App Store. Available as a desktop item.
As you have a Windows 7 Acer computer, you will not be able to play any games designed for Apple Macintosh, whether be from the iTunes Store or the App Store.
There are Windows PC competitors with the App Store. I would Google search them to find out more.
Or you could splash out on an Apple Mac and game in super high graphics with whatever you would do with a Mac for your day job...
Good luck and happy gaming!