Here’s the relevant content from the plugin page:
You can use get_author_post_rating( $post_id ) and the_author_post_rating( $post_id ) in your templates. Passing the post ID is optional, if you don’t include it the plugin will use get_the_ID() to try and figure it out for itself. You can pass the current post ID, or the ID of another post if you wish.
get_author_post_rating() will return the numeric post rating, if the post has one. This value does not include the HTML markup or star images which would surround the post rating on a normal post, it just returns the rating value itself.
the_author_post_rating() will echo the post rating along with the label and star images. Optionally, you can set the second parameter to true to return the markup instead of echoing it, like this:
$rating_markup = the_author_post_rating( $post_ID, true );
In your case you’d want to use the the_author_post_rating() function, which will actually display the rating along with the label and stars, instead of just getting the post meta rating value with the get_post_meta() function.