Cart page custom Cost price problem

Hello,

I having some trouble with displaying total cost column on the cart page. I have added the unit cost price column in the cart page through custom module which is perfectly fine. Now i want to show one more column which will calculate the total cost price according to quantity. Eg quantity * cost price = total price

Please help
this is the coding i have used soo far in the custom cost price column

function custom_form_uc_cart_view_form_alter(&$form, &$form_state) {

$form['items']['#columns']['price'] = array(
'cell' => t('Unit Cost'),
'weight' => 3.5,
);

}
function custom_tapir_table_alter(&$table, $table_id) {

if ($table_id == 'uc_cart_view_table') {
foreach (element_children($table) as $key) {
if (!empty($table['#parameters'][1][$key]['nid'])) {
$node = node_load($table['#parameters'][1][$key]['nid']['#value']);
$table[$key]['price'] = array(
'#markup' => theme('uc_product_price',array('element' => array('#value' => $node->cost))),

);

}
}
}
}

Any help would be appreciated