Retrieved the value of this field and pass it as a param in the following function 

**app/code/core/Mage/Sales/Model/Order.php**

  

      public function sendNewOrderEmail()
        {
         /*Existing Code*/
         if ($this->getCustomerIsGuest()) {
                $templateId = Mage::getStoreConfig(self::XML_PATH_EMAIL_GUEST_TEMPLATE, $storeId);
                $customerId = Mage::getModel('customer/customer')->load($this->getCustomerId());
                $companyname = $customerId->getCompanyname();
                $storeID = $customerId->getStoreId();
            } else {
                $templateId = Mage::getStoreConfig(self::XML_PATH_EMAIL_TEMPLATE, $storeId);
                $customerId = Mage::getModel('customer/customer')->load($this->getCustomerId());
                $customerName = $this->getCustomerName();
                $storeID = $customerId->getStoreId(); // fetch your custom attribute
            }
            
            $mailer->setTemplateParams(array(
              'order'        =>  $this,
              'billing'      =>  $this->getBillingAddress(),
              'payment_html' => $paymentBlockHtml,
              'storeid'  => $storeID 
           ));
         }

After making this change. edit Transactional Email to include this param. 
       Go to System > Transactional Emails > New Order Email and add like below :   

 
     {{ var companyname }}
     {{var order.getShippingAddress.format('html')}}

 hen this would get displayed in your Order Email in 'Shipping Address' Information right at the Start

**P.S.** I would advice you to override the core blocks instead of making changes in the core