This download contains the Windows Support Software (Windows Drivers) you will need to support Windows 7 on your Mac.
For more information on which operating systems are supported on different Mac systems, click here. : http://support.apple.com/kb/HT5634
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.
For more information on Boot Camp, click here www.apple.com/support/bootcamp