Flash News Ticker

Hello,
I’m new in WordPress and PHP.. I’ve managed to make a flash News Ticker by tampering around with the wp-rss.php file to make an XML file so flash could read it

<?php
	if (empty($wp)) {
		require_once('wp-config.php');
		wp('feed=rss2');
	}
?>
<?php echo '<?xml version="1.0" encoding="'.get_option('blog_charset').'"?'.'>'; ?>
<rss version="2.0" xmlns:content="http://purl.org/rss/1.0/modules/content/"	xmlns:wfw="http://wellformedweb.org/CommentAPI/" xmlns:dc="http://purl.org/dc/elements/1.1/" <?php do_action('rss2_ns'); ?>>
	<channel>
		<?php while( have_posts()) : the_post(); ?>
		<item>
			<title><?php the_title_rss() ?></title>
			<link><?php permalink_single_rss() ?></link>
			<date><?php echo mysql2date('D, d M Y', get_post_time('Y-m-d H:i:s', true), false); ?></date>
		</item>
		<?php endwhile; ?>
	</channel>
</rss>

This script shows/list all my entry title, permalink and posting date…
The thing is, I want to List ONLY the entries posted on certain category… such as HOT NEWS… I know nothing of PHP syntax so can anyone help me…
any help will be much appreciated…Thank you