If the box is not hd the pictures it produces won't be.
It may be possible to connect them through an adapter that has hdmi at the tv end and scart/rca/svideo at the box's, but even an "upscaled" image isn't really hd...could be an improvement though?
May also look worse as by upscaling the tv is kinda making up the missing pixels by stretching the image...
What is the make/model of tv, is there an option to make the image on the screen "HD"
(My sony has options of 1080p or i /720p or i/ standard/ auto)