Hi,
You can add a bit of HTML around it.
For example, you could change the line:
$t = $currencyHelper->format($data->cart->order_shipping_price,$data->cart->order_currency_id);
to:
$t = '<b>'.$currencyHelper->format($data->cart->order_shipping_price,$data->cart->order_currency_id).'</b>';
To get the discount value, it's more complex. It requires looking in $data->cart->products, extract the order_product_discount_info serialized data, unserialize it and look in that object. You'll need a programmer to work on this.