On 2nd thought, what exactly are you wanting to do? Do you simply want to shrink the entire file down to a size within 4.7 gig? Or are you wanting to trim off the end and continue with a 2nd DVD?
Well, then my original reference to TMPGEnc will work. The only thing I'm not sure about is the audio portion. I'm not sure if it can do AC3, if that is what your audio is.
In any event, there certainly are programs out there that will do what you want.
If you have either Ulead Media Studio Pro or Video Studio, it can ingest the MPEG, cut it, and not re-render the MPEG portion. It also accepts AC3 on the timeline.
You can either use Womble or TMPGEnc to cut the mpeg stream and you should be fine.
As for the AC-3 Audio, it's not a problem, since I assume you made elemetary streams anyway so yuo can just re-render the AC-3 in Vegas, that shouldn't take too long.