Never mind. I found the solution to staying on the same page. Odd since I was actually searching for something else and came across it...
I had to edit the file in /includes/modules/product_listing.php
and replace this code with the existing one
// qty box with add to cart button
if (PRODUCT_LIST_PRICE_BUY_NOW == '2' && $listing->fields['products_qty_box_status'] != 0) {
// $lc_button= zen_draw_form('cart_quantity', zen_href_link(zen_get_info_page($listing->fields['products_id']), zen_get_all_get_params(array('action')) . 'action=add_product&products_id=' . $listing->fields['products_id']), 'post', 'enctype="multipart/form-data"') . '<input type="text" name="cart_quantity" value="' . (zen_get_buy_now_qty($listing->fields['products_id'])) . '" maxlength="6" size="4" /><br />' . zen_draw_hidden_field('products_id', $listing->fields['products_id']) . zen_image_submit(BUTTON_IMAGE_IN_CART, BUTTON_IN_CART_ALT) . '</form>';
$lc_button= zen_draw_form('cart_quantity', zen_href_link($_GET['main_page'], zen_get_all_get_params(array('action')) . 'action=add_product&products_id=' . $listing->fields['products_id']), 'post', 'enctype="multipart/form-data"') . '<input type="text" name="cart_quantity" value="' . (zen_get_buy_now_qty($listing->fields['products_id'])) . '" maxlength="6" size="4" /><br />' . zen_draw_hidden_field('products_id', $listing->fields['products_id']) . zen_image_submit(BUTTON_IMAGE_IN_CART, BUTTON_IN_CART_ALT) . '</form>';
Thanks for you help.