Woocommerce - set total price before payment

I add a fee via php in review-order.php:

<?php   
    global $woocommerce;
    $total =  number_format($woocommerce->cart->total, 2, '.', ' ');

    $total = (float) number_format($total, 2, '.', ' ') + (float) number_format($vvk, 2, '.', ' ');
    $total = number_format($total, 2, ',', ' ');
?>

    <tr class="order-total">
        <th><?php _e( 'Total', 'woocommerce' ); ?></th>
        <td data-title="<?php _e( 'Total', 'woocommerce' ); ?>">
            <?php echo "<strong><span class=\"amount\">€".$total."</span></strong>"; ?>
        </td>
    </tr>

Now i need to update the total price before payment.

Any ideas? Thanks.