display BUY NOW as a button and not text

great plugin thank you!

The BUY NOW/GO TO… is now a text link and gets lost on the page. Can you tell me how to show the button please.

Huge thanks.
M

http://lindsay.odrumtestsite.com/product/the-values-driven-organisation-richard-barrett/

https://wordpress.org/plugins/woocommerce-improved-external-products/