authors listing codes

Hi guys, i need authors listing codes, i cannot found i tried every codes in my site. But not working. i just wantto get all authors last one entry. For example

Jason Junior
This is my last topic
and left one my author image.

i have 4 author in my site. i want listing this authors. with avatar and last entry. how can we do? could u help me?

and other i want 1 code when i add new author with enrty it must be showin…

my last codes

<div class="grid_7 yellowish yazarpaneli">
<img aling="middle" src="<?php echo get_template_directory_uri(); ?>/images/koseyazari.png" width="330" height="61" alt=""/>
<?php
// Get all users order by amount of posts
$allUsers = get_users('orderby=post_count&order=DESC');

$users = array();

// Remove subscribers from the list as they won't write any articles
foreach($allUsers as $currentUser)
{
	if(!in_array( 'subscriber', $currentUser->roles ))
	{
		$users[] = $currentUser;
	}
}

?>

<section class="content" role="main">
	<?php
			foreach($users as $user)
		{
			?>
  <div class="grid_6 ustmargin5 thumbnail">
    <div class="floatright">
            <?php echo get_avatar( $user->user_email, '128' ); ?>
    </div>
            <h4 class="solpadding5"><?php echo $user->display_name; ?></h4>
            <p class="solpadding5">
      <!-- AUthor Last entry -->
  How Can i in there last topic?

            <!-- AUthor Last entry -->
            </p>
            </div>
	<?php
		}
	?>

</div>