How do I make RSS feed for posts comments?

I have been using WordPress for just few months so I’m not experienced in editing files.

I want to make RSS comments link for every post I make so my readers can easily be updated of new comments for a post.

I know that I need to edit the comment file but I don’t know what to put in and where, so I ask if you can help me to do it.

The comment file for the theme I’m using is this:

<?php // Do not delete these lines
 if ('comments.php' == basename($_SERVER['SCRIPT_FILENAME']))
  die ('Please do not load this page directly. Thanks!');

        if (!empty($post->post_password)) { // if there's a password
            if ($_COOKIE['wp-postpass_'.$cookiehash] != $post->post_password) {  // and it doesn't match the cookie
    ?>

    <p class="nocomments"><?php _e("This post is password protected. Enter the password to view comments."); ?>

    <?php
    return;
            }
        }

  /* This variable is for alternating comment background */
  $oddcomment = "graybox";
?>

<!-- You can start editing here. -->

<?php if ($comments) : ?>
 <h2 id="comments"><?php comments_number('No Responses','One Response','% Responses' );?></h2> 

 <ol class="commentlist">

 <?php foreach ($comments as $comment) : ?>

  <li class="<?=$oddcomment;?>" id="comment-<?php comment_ID() ?>">

	<strong><?php comment_author_link() ?></strong>

	<p class="commentmetadata"><a href="#comment-<?php comment_ID() ?>" title=""><?php comment_date('F jS, Y') ?> at <?php comment_time() ?></a><?php edit_comment_link('Edit comment',' ~ ',''); ?>

   <?php comment_text() ?>

  </li>

  <?php /* Changes every other comment to a different class */
   if("graybox" == $oddcomment) {$oddcomment="";}
   else { $oddcomment="graybox"; }
  ?>

 <?php endforeach; /* end for each comment */ ?>

 </ol>

 <?php else : // this is displayed if there are no comments so far ?>

  <?php if ('open' == $post-> comment_status) : ?>
  <!-- If comments are open, but there are no comments. -->

  <?php else : // comments are closed ?>
  <!-- If comments are closed. -->

  (comments are closed).

 <?php endif; ?>
<?php endif; ?>

<?php if ('open' == $post-> comment_status) : ?>

<h2 id="respond">Leave a Comment</h2>
<form action="<?php echo get_settings('siteurl'); ?>/wp-comments-post.php" method="post" id="commentform">

<input type="text" name="author" id="author" value="<?php echo $comment_author; ?>" size="22" tabindex="1" class="styled" />
<input type="hidden" name="comment_post_ID" value="<?php echo $id; ?>" />
<input type="hidden" name="redirect_to" value="<?php echo htmlspecialchars($_SERVER["REQUEST_URI"]); ?>" />
<label for="author">Name</label>

<input type="text" name="email" id="email" value="<?php echo $comment_author_email; ?>" size="22" tabindex="2" class="styled" />
<label for="email">Mail (will not be published)</label>

<input type="text" name="url" id="url" value="<?php echo $comment_author_url; ?>" size="22" tabindex="3" class="styled" />
<label for="url">Website</label>

<!--<strong>XHTML:</strong> You can use these tags: <?php echo allowed_tags(); ?>
-->

<textarea name="comment" id="comment" cols="100%" rows="10" tabindex="4" class="styled"></textarea>

<?php if ('none' != get_settings("comment_moderation")) { ?>
 <small><strong>Please note:</strong> Comment moderation is enabled and may delay your comment. There is no need to resubmit your comment.</small>

<?php } ?>

<input name="submit" type="submit" id="submit" tabindex="5" value="Submit Comment" />

</form>

<?php // if you delete this the sky will fall on your head
endif; ?>