if you don't want the quality to be bad when you export, you'll pretty much have to export uncompressed, or with Huffyuv or lagarith.
you could take a chance and try to encode using vegas, but I wouldn't be too suprised if it doesn't turn out great.
4 minutes uncompressed video: ~6.5GB
4minutes compressed with huffy: ~1GB
lagarith: ~850MB
one way to free up space is to delete the .vob files when you're done with them (1 episode takes about 1GB)
there are probably a few programs that you have installed that you don't use [often or at all]
or files from years (and classes) long past






