I have the 722 downstairs hooked up to my hdtv. Upstairs is a regular tv. A coaxial comes out of the wall into that tv. I want to replace that with an hdtv. The person at dish said I would need a new, spearate DVR upstairs to get high def. IS thius true? I guess it makes sense since there is presenly a coaxial coming out of the wall so that doesn't carry a high def signal.