in the code provided earlier in this topic, you can edit the parameters for the 'get-purchase-options' and override the standard label using the 'add-to-cart-label' parameter, e.g. "Add to Cart" is changed to "Get this" using the following code:
it_exchange( 'product', 'get-purchase-options', array( 'add-to-cart-label' => 'Get this', 'add-to-cart-edit-quantity' => false, 'buy-now-edit-quantity' =>true ) );
That might be a clue,
As for changing the color, that may be done using css, but I am not sure if there is a class for the "clicked" state, you should inspect your site, FIrebug is recommended.
Also, please (always) add a link to your site so we can look into this if need be,