I have a div that displays the total amount of products the customer has in their cart, however this isn't updating as I have caching on (W3 Total Cache).
Is there a workaround for this?
Read the WooCommerce docs. I've run in to this before, and the following pages cannot be cached:
You would need to use what's called "fragment caching" to regenerate only part of the page each time. http://css-tricks.com/wordpress-fragment-caching-revisited/
First, try these common Solutions that have worked for others:
Disable your caching plugin (which can cause the JS to stop working) and see if that fixes it
Try using a different browser but as a user, not ADMIN
Go to your WooCommerce settings page and Untick "Prepend product permalinks with shop base page (shop)"