What you can do is download the MP3 from the lessons (by clicking on the Jam tab then selecting "download"). That way you just have the audio file to work with, and there are a lot of programs that can slow down audio.

The one I use is called The Amazing Slow Downer. The full version costs $50, but trust me it's worth it. You can learn anything no matter how difficult it is because you can slow it down as much as you want, master it, then slowly speed up.

Here's the link: http://www.ronimusic.com/