You can use the Boot Camp drivers that your Mac OS X DVD contains, but they are outdated.
As you are running OS X Mountain Lion, it's much better to download Boot Camp drivers from Boot Camp Assistant. To do it, just open Boot Camp Assistant, press "Continue" and tick the options to download Windows support software and install Windows 7. It will be downloaded and Boot Camp Assistant will ask you to burn it into a DVD or USB drive, so do it.
After doing that, Boot Camp Assistant will ask you for the space you want for Windows, so select it, insert the Windows installer DVD and your Mac will restart to start the installation.
If you need help to install Windows, print this file > http://manuals.info.apple.com/en_US/boot_camp_install-setup_10.7.pdf
You have to install Boot Camp drivers just after finishing the Windows installation