No, you are not correct. HD begins as high quality video, it isn't cruddy video run through the magic HD machine to make it look so good.
Video processing will already be built into your Sony set. Get it first, hook things up, then if you want to try a video processor, be darn sure you buy from a place with a liberal return policy. I have used DVDO products, and while they can improve an image, I do not think the improvement is tremendous. It is marginal - at best. Quite often, it shows almost no improvement in image quality over the video processors that are inside the set already. A video processor's job is to change 480i and 480p into the native resolution of your display. It may do this very well, but your display already must change 480i and 480p into the native resolution of the display. The bottom line is that it still begins as 480 lines of 4:3 material - and can't be HD no matter what you do to it.