If I just went with Photoshop Elements 11, that would probably fulfill all my needs, but it's difficult to be sure that I would never want the more capabilities with the full Photoshop and as my upgrade eligibility lapses, I would lose my previous investment in the full Photoshop...I was thinking about usability trade-offs between using either full Photoshop or Photoshop Elements in conjunction with PRE 11.
To present a balanced picture, I would strongly recommend looking at the trial version of Photoshop CS6 as well as the one for Photoshop Elements 11 before making your decision. There have been quite a few changes to Photoshop since your version and there is a lot of added capability. Some of this capability has made its way into Photoshop Elements, but generally in a more basic and less flexible form. Photoshop Elements may very well meet all your current needs. But, as you gain more experience and knowledge, you may find yourself wanting more. Try out the features in the two products and consider whether the differences are something that may matter to you.
As far as working with Premiere Elements 11, both products can be used. The integration of Photoshop Elements and Premiere Elements is rather basic. Premiere Elements can pass a snapshot directly to elements, whereas you will need to save the snapshot as a file and open in in Photoshop. The Organizer can be used with both Photoshop Elements and Photoshop if desired. And, you can edit and modify DVD templates in both Elements and CS6 although CS6 will have more capability with layer groups.
One interesting new development is that the standard version of Photoshop CS6 now has the capability to edit video. This capability was intended for still photographers who were wanting to do something with the video they captured with their still cameras and who didn't want to learn another program. It's pretty rudimentary compared to Premiere Elements, but the interesting thing is that you can add adjustment layers and apply filters similar to how you would work with still photos. This presents the opportunity to use Photoshop for some of your video work, export it to a video file and then import and finish editing in Premiere Elements.
Something to think about.