Where can I get bootcamp?

Hello Apple World, I have a minor issue. If I do not currently own a copy of bootcamp, how would I go about aqcuiring this piece of software? You see, I reently got my iMac back from an Apple Store, and after reinstalling the Operating system, and installing bootcamp, it simply wasn't there anymore, it appeared that the application simply got rid of itself, but it doesn't matter why I don't hve it, back to the point. Could I download it from an official site? Or would I have to go to the apple store and ask for a disk of it, or for them to install it. Or am I simply out of luck and would have to purchase an entirely new apple computer to acquire bootcamp? Please respond, and thank you.