I have OS X 10.6.6 but need 10.8.8 or higher for software I want to run. How best to upgrade?

Do you mean you need 10.8.8 ? Or did you mean 10.6.8 ?

There is no 10.8.8. The current version of the Mac OS is 10.8.2.

If you need 10.6.8, simply to to the Apple Menu and select “Software Update”. This will update your Mac from 10.6.6 to 10.6.8.