Position of the “add to cart” button

Hi,
in the page of the link that I have indicated you can see that the blue button “add to cart” (translated “aggiungi al carrello”) is positioned to the right of the module (text box and radio box) created with your plugin.
How can I do to place the button at the bottom of the module?

Thanks

Giusy P.

The page I need help with: [log in to see the link]