How to get attribute "option label/attribute text" having "attribute value" (option_id)?

In addition to your code put this:

$product = Mage::getModel('catalog/product')
                ->setStoreId($store_id)
                ->setBrand($brand_value); // not loading the product - just creating a simple instance
$brandLabel = $product->getAttributeText('brand');

$attribute = Mage::getModel('catalog/resource_eav_attribute')
            ->loadByCode(Mage_Catalog_Model_Product::ENTITY, 'manufacturer');
$label     = $attribute->getFrontendLabel();