How to buy 2 version of product on same page??

[futuremindtraining]

Hi

Im looking to put to options of puchase of my audio product on the same page

Option 1: Hard copy cds £18.99
Option 2: Audio download (from shop £15.99

http://shop.futuremindtraining.co.uk/2-audio-recordings (this is the page (science and psychology of social manipulation at the moment is in to pages)

if the customer buys cds i need it to act as normal and if the customer buys the audio download i need it to go to download page

So in essence a dop down tab or button which will chagne the type of product hard copy or download

ps if you are doing audio download i recommend presto chango batch downloads
http://www.presto-changeo.com/en/prestashop-modules/38-batch-downloadable-product.html

thanks in advance