To get catalog product data of particular category/product you can use below code
$id = 3; // need to pass id of particular category
$store_id = 1; // need to pass store id if you have multiple store
$currentCategory = Mage::getModel('catalog/category')->setStoreId($store_id)->load($id);
$collection = $currentCategory->getProductCollection();
$collection->load();
foreach ($collection as $product):
$product = Mage::getModel('catalog/product')->load($product->getId());// need to pass product id if want to load particular product
$product_id = $product->getId();
$product_name = $product->getName();
$product_price = $product->getPrice();
$product_img = Mage::getModel('catalog/product_media_config')->getMediaUrl( $product->getImage());
endforeach;