Elliot,
As of May 20, 2015 PreSonus released Studio One v3 and no longer sells version 2 or its Studio One v1 Upgrades to version 2.
- this shifted the product versions that are available directly from PreSonus Audio
There are some re-sellers out there whom still may have some older upgrade copies for sale, but as it now is almost 2 years since the release of version 3; they are becoming harder and harder to locate. You may luck up and find someone whom either has an upgrade for sale or maybe even a copy of version 2 for sale; either new or used.
**please keep in mind that your OS version, OSX 10.7, is now 5 full OSX versions behind the most current version of macOSX. You will need to start thinking about updating your system, as you will find more and more software vendors are no longer supporting such an old OSX version.