Hi,
That's great then. My concerns were unfounded 
So first you need to change the "Price display method" option to "all" for your menu via the menu Display>Content menus.
That way the system will load both prices.
Then, you'll have to remove the code:
$this->setLayout('listing_price');
echo $this->loadTemplate();
which would actually display both prices one below the other, and add instead such code:
echo $this->currencyHelper->format(@$this->row->prices[0]->price_value,4);
echo '</td><td>';
echo $this->currencyHelper->format(@$this->row->prices[1]->price_value,4);