Moving the “share” button

Well you can do this with css as well, to add button before add to cart, add the following css code in your theme style file i.e : style.css

.ywsfd-social {
    position: absolute;
    bottom: 12%;
    left: 40px;
    margin: 15px 0px;
}

it will work ok till 1024 screen, you have to add media query to perfectly fit it in smaller screens.