Remember the Adobe Creative Cloud deal I talked about back in September? Well Adobe has a limited time deal (until Dec 2, 2013) where they will offer it to anyone, even if you don't have PS CS3, like the previous version of this deal.
Here is the Adobe page that has all the details and links to sign up.
Even if you are not a fan of Creative Cloud the only way you are going to get access to future updates to Photoshop you are going to have to subscribe to Creative Cloud, and this looks to me like the cheapest way to do it.
I signed up yesterday mainly because I can't live without Photoshop, and this is a cheap way to get both PS CC and LR going forward.