For Image Url, you can use
$image = Mage::getModel('catalog/product_media_config');
$product = Mage::getModel('catalog/product')->load($your_product_id);
$thumbnail_path_url = $image->getMediaUrl($product->getThumbnail());
$smallimage_path_url = $image->getMediaUrl($product->getSmallImage());
$image_path_url = $image->getMediaUrl($product->getImage());
For Category name, you can use
$_cat = Mage::getModel('catalog/category')->setStoreId(Mage::app()->getStore()->getId())->load($your_category_id);
$catname = $_cat->getName();
Fetch these values separately and bind it to your existing fields.
What I provided was a general way of getting the Url path.
If you need to override the core magento Export functionality to add URL to image you can Check this
Link