Apple Boot Camp Support Software for Mac

Boot Camp enables you to install Windows on your Intel-based Mac computer, using a
Microsoft Windows install disc that you provide. Windows is installed on its own
partition. After installation, you can use either Windows or Mac OS X on your Mac
computer.

The download file is a .zip file. Double click it to uncompress it.
Double-click the Boot Camp disk image.
Copy the entire contents of the .zip file to the root level of a USB flash drive or hard drive that is formatted with the FAT file system
For detailed information about this update, please visit: http://support.apple.com/kb/HT5628
When running Windows, locate the Boot Camp folder on the USB media you created in Step 3 and double click to open it.
Double click on setup to start installing the Boot Camp Support Software.
When prompted to allow changes, click on Yes and follow the onscreen instructions.
Installation can take a few minutes. Don't interrupt the installation process. When installation is complete, click Finish in the dialog that appears.
A system restart dialog box appears. Click Yes to complete the installation.