How to use virtuemart models in my custom components?

[BillyMontoya]

I have developed a custom component to import different types of data in virtuemart. I am facing trouble to load virtuemart module in my custom component. I am using Joomla 3.4.1 and virtuemart 3.0.6.2

I have tried several ways to load model to my component.
I have tried following

JLoader::import('joomla.application.component.model');
JLoader::import( 'manufacturer', JPATH_ADMINISTRATOR . DS . 'components' . DS . 'com_virtuemart' . DS . 'models' );
$model = JModel::getInstance( 'Manufacturer', 'VirtueMartModel' );

is there any way to get model?

[GJC Web Design]

if (!class_exists( 'VmConfig' ))
require(JPATH_ADMINISTRATOR.DS.'components'.DS.'com_virtuemart'.DS.'helpers'.DS.'config.php'); // make sure DS is defined in your comp
e.g.
defined('DS') or define('DS', DIRECTORY_SEPARATOR);

$model = VmModel::getModel('Manufacturer');
$manufacturers = $model->getManufacturers(true, true,true);

I am using Joomla 3.4.1 and virtuemart 3.0.6.2

both way out of date and insucure