file too big

My file is too big to make a dvd it appears. How can I burn a portion without deleting the excess? I see no way to burn a looped portion like I would to upload to youtube. Any suggestions? I dont want to delete part because I would have to re edit it again. Right now it saves as an AVI. I need the audio that goes with it. Render it as something else which saves the audio? Which one is that? Right now it outputs as HDV Camera (1080). I suppose if the output type was changed to DVD it would probably be small enough. But I don't know how to do that.
Thanks Doyal