Getting text from a website?

[rscape]

<?php

$rs = file_get_contents("http://runescape.com/index.ws");

$pos = strpos($rs, '<fieldset class="menu poll">');
$number = substr($rs, $pos + 1, 100);
$pos = strpos($number, '</fieldset>');
$number = substr_replace($number, '', $pos);

echo $number; 

?>

Thats the code I'm using right now, but it dosn't work for the text I'm trying to get, the text is multi lined, this is the text:-

<fieldset class="menu poll">
<legend>Latest Poll</legend>
<div style="width: 90%;">
What would you do #3
</div>
<ul>
<li class="i-vote"><a href="http://poll.runescape.com/latestpoll.ws">Vote in this poll
(Members Only)
</a></li>
<li class="i-polls"><a href="http://poll.runescape.com/index.ws">Poll Home</a></li>
</ul>

</fieldset>

The words "What would you do #3" change every week, can anyone see something wrong in the code?