Ok, we checked your site and the button on the right side can not be moved down because this button in the code is in the same place as coupon field. And until WooCommerce author won't change this behave, it won't be possible to control that button. In this case, we can give you the code to move the button on the right side but coupon on the left. This can be done with below css:
Comments
please send us url to page where you got this problem and we'll have a look on it.
.woocommerce .cart .button, .woocommerce .cart input.button { float: right !important; }