You can handle both these issues by first selecting the media on the Media tab of the Project Pane, selecting the clip in question, then selecting the Media tab of the Inspector.
To slow down the footage, you can choose a lower frame rate. Not great, but it will work. For a better solution, use FCP and export a movie.
To extend, change the End Condition to Loop or Ping Pong - then you can drag out the movie as long as you like.