Poonya,you can load the product by  product id
 

    $pro=Mage::getModel('catalog/product')->load($_product->getId());
    $OrgPrice=$pro->getPrice();
    $finalPrice=$pro->getFinalPrice();
Hope ,it will help you..
Or Goes to `app/code/core/Mage/Catalog/Product/List.php` copy to  `app/code/local/Mage/Catalog/Product/List.php` then

find function 

    getLoadedProductCollection()

         public function getLoadedProductCollection()
           {
                $Collection=$this->_getProductCollection();
     $Collection->addMinimalPrice()
                ->addFinalPrice();
    return  $Collection; 
    
            }