Once you have imported the image sequence and exported in your preferred format from Virtual dub you can use Windows Movie maker as a crude editor. There are facilities within Blender to achieve NLE. (Non Linear Editing), but unless you are already familiar with Blender it could prove , ummm.... errr... welll.....let's say tricky and leave it at that.
I've never really delved into free editing sw because I am fortunate enough to have access to commercial sw at work.
Hope this helps a bit..
Rgds
Chris