Magento

Actually i want to change in table rate shipping method. i changes in excel sheet. but i want to display in front side.

So changed function like as

public function getPrice()
{
return $this->_getData(’price’);
}

in catalog /model/product.php

now i made new function

public function getPrice_new()
{
return $this->_getData(’cost’);
}

And I call This function as::::<?php echo $_rate->getPrice_new() ?>

but my server could not find this function...Why??????????????????
If I wrote <?php echo $_rate->getPrice() ?> it gives me value.