based on my experience, you may import your swf, provided it was not published with the protect tab on, into a new fla but you loose your code and sound. there's no way you can convert swf to fla. think of it this way, swf is a glass bottle. whatever you do to the bottle, you can never extract the sand out of it. sorry for the bad news bro, guess u just have to do it all over again.
biggie