magento - convert order amount from current currency to base currency

I am trying to convert order amount from current currency to base currency, below is the code which i tried, but no go.

$baseCurrencyCode = Mage::app()->getStore()->getBaseCurrencyCode(); 
$currentCurrencyCode = Mage::app()->getStore()->getCurrentCurrencyCode(); 
$price = 1; 

$priceTwo = Mage::helper('directory')->currencyConvert($price, $baseCurrencyCode, $currentCurrencyCode);