How do i add author link and avatar

I have installed third party theme on WordPress blog and it does not support author link or author avatar. I have tried by adding the code- by <?php the_author_posts_link(); ?> but it displays below my comments box.
My single-post.php file:

<?php global $theme; get_header(); ?>

    <div id="main">

        <?php $theme->hook('main_before'); ?>

        <div id="content">

            <?php $theme->hook('content_before'); ?>

            <?php
                if (have_posts()) : while (have_posts()) : the_post();
			/**
                     * Find the post formatting for the single post (full post view) in the post-single.php file
                     */
                    get_template_part('post','single');
                endwhile;

                else :
                    get_template_part('post', 'noresults');
                endif;
            ?>
          by <?php the_author_posts_link(); ?>
            <?php $theme->hook('content_after'); ?>

        </div><!-- #content -->

        <?php get_sidebars(); ?>

        <?php $theme->hook('main_after'); ?>

    </div><!-- #main -->

<?php get_footer(); ?>

where do i add code so that it can be displayed just after the title on single post. You can also visit my site to know about the theme- justsharehere.com