echo get_post_meta($postid,'meta_key_name',true); is what you want if the plugin is storing data as individual keys in the post meta table. You may be dealing with an array of values though which would require something like:

$meta_data = get_post_meta($postid,'meta_key_name');
// var_dump($meta_data); // debugging
echo $meta_data['some_key'];
echo $meta_data['another_key'];

As you don’t even name the plugin or provide a link to it (that I can see) it is hard to say more. The plugin may not even be saving data to post meta. I could be saving to the options table or to a table of its own creation.

Reference:

http://codex.wordpress.org/Function_Reference/get_post_meta