Import the swish file into Flash Then select the frames and right click copy. Now goto insert new symbol name it and check the movie as the symbol type. Flash will automatically bring up the movie click stage right click in the first keyframe and choose paste frames from the pop up menu. return to the main time line and click window library and drag the movie clip you just created onto the stage and position it where you want it. From now on make sure you movie from swish has the text positioned where you like and make the swish movie size match that of your Flash movie to avoid this problem.
Whenever I work with gifs, my first stop is http://www.gifoptimizer.com where I reduce the amount of colors to a level that is still acceptable but with a smaller filesize. Try that on your banner clips.