I have filmed a theater play in HR and have edited it in HR but the final product does not appear to be very high resolution. Any ideas as to what I am doing wrong?
If you are burning to DVD the resulting video will be SD, Standard Definition, whatever the "input" quality may have been. That is one of the "limitations" of the DVD format.
Your only options to obtain true HD output is to either burn to a DVD disc as AVCHD or to burn as full Blu-ray. In either case you will need a Blu-ray player to play back your finished disc.
Or export in HD (say as MP4) and then either stream to your TV (I use a WDTV unit, wirelessly receiving from my PC upstairs) or simply watch it on your large screen PC monitor.
But of course, that's not a solution for viewing by others outside your home!