How do I access content variables in a custom block?

I have a block, that I made with the Views module.
The content comes from a custom content type I made with the CCK module.

My block's name is "middle", so I took the default block.tpl.php and copied that to a new file: block-middle.tpl.php.
That file looks like this:

<?php
// $Id: block.tpl.php,v 1.3 2007/08/07 08:39:36 goba Exp $
?>
  <div class="block block-<?php print $block->module; ?>" id="block-<?php print $block->module; ?>-<?php print $block->delta; ?>">
    <h2 class="title"><?php print $block->subject; ?></h2>
    <div class="content"><?php print $block->content; ?></div>
 </div>

I see where the content is output (print $block->content) ... but how do access the "sub-variables" in "content"?
For example, there is an image within the content, and instead of that just being output as an image, I need it to be output as a background in a div.

So what I'm looking for is something like this:

<div class="content">
    <div style="background-image: url(<?php print $block->content->MyImage; ?>);">
        <?php print $block->content->MyText; ?>
    </div>
</div>

I hope this makes sense... :)
How do I do it?