How to get the do not disturb button on my iphone 4s?

I have an iphone 4s. I didn't download ios 6 because i don't have enough room on my phone. And it is too much of a hassle. I have seen it before in my settings. How can i get the "do not disturb" button back without downloading anything or apps?

You can only get it with iOS 6 sadly. No other way

Update to ios 6.1