Hi,
I must say that we didn't handle the export of brands. We'll add that to the export in the next version.
For now, you only get the brand id in the "product_manufacturer_id" field of the products in the CSV when you export your products.
So if you already have your brands on the new website with the same ids as the old website, the import will like the products with the brands automatically during the import.
So the best would be to export your brands from the hikashop_category table of your old website and import them in the same table of your new website via phpmyadmin and then click on the "rebuild" button of the categories listing in the backend of your new website and that should add all the brands with the same ids on your new website.