Sorry, Linda. I'm on call this weekend and was in Portland taking care of patients.
Apparently, CS6 is still available as a stand-alone version. B&H has CS6 available for $300 for teachers, $670 for the unwashed masses. See here:
Unfortunately, trying to find the price of the upgrade I found myself in a (too typical) Adobe online merry-go-round. I suspect the quickest way would be to give them a call on Monday. I've always been surprised when calling the Adobe help desk, as the helpers 1.) actually speak English, and 2.) seem able to answer questions straightforwardly.
There is, more over, an option to purchase Photoshop CC and Lightroom in the cloud for $10 a month, in perpetuum. Or as "perpetuum" as Adobe may deem necessary. For which currently I wouldn't give you a nickel. A personal opinion.
I take it you didn't sign on for the $50 a month CC suite?