the best thing to do is to get them into a .avi format first. from memory you can do this in movie maker in the render options. Get a good codec also like one of the DivXs or XVid from
http://www.doom9.org (lotsa good tools there in the download section) then use something like VirtualDub (the free version - Google it) to edit it.
Lovely clips by the way - would love to see the other one!