Extract url from the post

I have blog post in wordpress for audio podcast like

[audio mp3="http://www.andrewbusch.com/wp-content/uploads/show_6195505.mp3"][/audio]
We talk the latest with forward guidance in the Federal Reserve with Wall Street Journal reporter, Jon Hilsenrath.

want to make a download link also for the above mp3 url inside the loop.

How to extract the url from the above content?

I tried like the below but it is not working

<div class="banner-text">
<h1><a href="<?php the_permalink(); ?>"><?php echo the_title(); ?></a></h1>
<?php the_content(); ?>
<?php
$content = get_the_content( $more_link_text, $stripteaser );
preg_match_all('#\bhttps?://[^\s()<>]+(?:\([\w\d]+\)|([^[:punct:]\s]|/))#', $content, $match);
$match = $match[0];
?>
<div class="banner-download"><a href="<?php echo $match; ?>"><span class="displace">Download</span></a></div>
</div>

Any help ?