Show authors in sidebar with info and picture

Hello guys
I have a Article Marketing blog, i like show last 5 or 10 authors on sidebar with info and picture (gravatar or user photo) but i can find appropriate code for do this, so i find this code:

<h2>Recent Contributors</h2>
<div>
<?php

$limit = ’10';
$query = “select post_author as ID, max(post_date)
from $wpdb->posts
where post_type = ‘post’ and post_status = ‘publish’
group by post_author
order by 2 desc
limit $limit;”;
$usersinfo = $wpdb->get_results($query);
foreach($usersinfo as $userinfo){
$user = get_userdata($userinfo->ID);
$user->postcount = $userinfo->postcount;
?>

<div>
<?php if( $user->aim != ”){ ?>
<img width=”57" alt=”<?php echo $user->aim; ?>”   src=”<?PHP echo $user->aim; ?>” />
<? }else{
?>
<img width=”57" alt=”no image”   src=”http://www.geekestateblog.com/images/blankphoto.jpg” />
<?php } ?>
<ul>
<li><strong><?php echo $user->first_name;  ?> <?php echo     $user->last_name;  ?> </strong></li>

<?php if ($user->yim != ”){  ?>
<li><a href=”<?PHP echo $user->user_url; ?>”><?PHP echo $user->yim; ?></a></li>
<? } ?>

<?php if ($user->jabber != ”){ ?>
<li><a href=”<?PHP echo $user->jabber ?>”>Blog</a></li>
<? } ?>

<li> <a rel=”nofollow” href=”http://www.geekestateblog.com/author/<?PHP echo $user->user_login ?>”>View Posts</a> | <a rel=”nofollow” href=”<?php echo get_author_feed_link($user->ID); ?>”>RSS</a></li>
</ul>
</div>
<?php
}
?>
</div>

But it not work correctly, can help me please?