@Lynnpina, Yes you can use the Aweber Integration option to deliver the audio files over a period of time. You do this globally for every product or on a per product basis by specify the aweber list name in the “Autoresponder Settings” section of that product.
No, it is not possible to give the user an option to choose without customizing the plugin code. If you are okay with PHP and HTML then you can go for this customization though.