Currently Being ModeratedJan 4, 2013 4:42 AM (in response to gussima)
Installation disks are model specific so that version is not compatible with your Mac. You will have to purchase a retail copy of 10.6 from the Apple store and install 10.6 in your Mac, then use software update to install 10.6.8.
If your Mac qualifies for a Mt. Lion update, then purchase it from the App store and download it. Here are the requirements for Mt. Lion: