All you have to do is use the shortcode that displays the shopping cart at the top of the page… this way when someone adds a product it will be displayed at the top of the page.
If you want the page to open a new window when someone hits the “Add to Cart” button then search for the following in the “wp_shopping_cart.php” file:
$replacement = ‘<object><form method=”post” action=””
once you find the line replace it with the following:
$replacement = ‘<object><form method=”post” action=”” target=”_blank” style=”display:inline” onsubmit=”return ReadForm(this, true);”>’;