Php WordPress help

[JamesBlake]

I am writing the following code for making a plugin

<?php
header("Content-Type: text/css");
/*
Plugin Name: Name of the plugin.
Plugin URI: The page having information related to plugin.
Version: 0.1
Description: Your plugin description.
Author: Your name
Author URI: Author's website.
*/
?>
<?php
function box()
{
?><div class="box">
<p><b>Author:</b> <?php the_author_link(); ?><p>
<?php echo get_avatar( get_the_author_email(), '50' ); ?>
<p><?php the_author_description(); ?></p>
</div>
<?php
}
function style() {
echo "
<style>
<!--
.avatar{
float:left;
background-color: #fff;
border:1px solid #ccc;
padding: 4px;
margin: 0 7px 2px 0;
display: inline;
}
.box{
color: #666;
font-weight: normal;
background: #fff;
border: 1px solid #ccc;
padding: 12px;
margin-bottom:8px;
}
-->
</style>
";
}
function author_box_ContentFilter($content)
{
if (is_single())
return $content.box().style();
else
return $content;
}

add_filter('the_content', 'author_box_ContentFilter');
?>

This code is appending the author info box at the start of post.But i want to add the box a the end of post.I also tried

{
if (is_single())
return box().$content.style();
else
return $content;
}

But this is also not working.

Seeking for help to append the box at the end of post.

Thanks in anticipation

[JAY6390]

Suprisingly it's the same as the answer here

http://forums.digitalpoint.com/showthread.php?p=12963081#post12963081