Where's my HD menu on a HDXL TiVo?

I can't seem to access my HD menu and therefore any xfinity on demand programming..my HDXL tivo only shows standard definition screens and doesn't even give the option of HD under displays in settings. I've rebooted, made sure my hdmi cable is correctly inserted, my aspect ratio is at 16:9 and video is set at 1080p fixed.....tivo is telling me to exchange up to a premier but it's $278 with a lifetime service and I'd loose all my recordings. 'Any ideas?? THX!