Answer:

  1. Go to Theme Options > General
  2. Copy and paste the following into your Custom CSS box

 

.cart-collaterals{float: left; width: 100%;}
 
.cart-collaterals .cross-sells {float: left; width: 75%;}
 
.cart-collaterals .shop_table.cart{width: 100%;}
 
.cart-collaterals .cart_totals{float: right; width: 25%;}
 
.cart-collaterals .shipping_calculator {float: right; width: 25%;}
 
.cart-collaterals .sidebarnone .products .product {min-height: 280px; width: 30.5%;}