how to include other jquery file and css file in wordpress plugins

You should use this snippet inside your function:

wp_register_style('mycss', WP_PLUGIN_URL . '/whatever.css');
wp_enqueue_style('mycss');

Then you add this add_action after your function, to call your the CSS in the :

add_action ( 'wp_head', 'your_function_name');

For javascript, use wp_register_script() and wp_enqueue_script() instead.

WordPress function reference:
wp_enqueue_style and
wp_enqueue_script