Well, you can still work it, but it might be a little more work. I'm not at home right now, so I can't give you the list of programs I'm using off the top of my head.
pdiggs, try to take the mpg file you have, and under the file menu in TMPGenc (you should actually get the plus version, I forgot), there is an option that says "MPEG tools" or something like that. You might be able to do simple manipulations from there.
Other programs are DVD2avi that could probably read it. Check
www.vcdhelp.com for more help.