I'm afraid the answer is the same as it was to your other inquiry. It isn't a matter of the difference between Photoshop CS 5.5 and the Design Premium version. It is the version number. And Photoshop CS 5.5 Design Premium is still only compatible with Camera Raw up to 6.7. The DNG converter is still your best choice if you are not willing to upgrade your Photoshop.
But then I just realized that I didn't read your question very closely. The DNG converter doesn't work with any program. It is a separate standalone program that is used by itself to create DNG (digital negative) copies of your raw images. You can use the DNG converter as your download software, converting the images as they are being transferred to your computer. Then you will be able to open them with the older versions of Camera Raw that are compatible with your version of Photoshop. Some people are concerned that the DNG converter means an extra step. But if you use it as your download software I think you will find that it can streamline things considerably.
When configuring the DNG converter, make sure you choose a compatibility option that is compatible with your version of Camera Raw. Also, take note that the DNG converter prompts you for a FOLDER containing raw images. Choose the folder, but don't open it.