Hide Active Widgets Panel in Wordpress

Hide Active Widgets Panel in WordPress
This plugin needs improving, but I'm a code noob. I'd like to see the following improvements:
1. Allow admin access but restrict all other users
2. include the css file in the plugin (no editing needed)
3. have a checkbox to enable the hiding feature.

<?php

/*
Plugin Name: Hide Active Widgets
Plugin URI: http://wordpress.com
Description: Hides the Active Widgets from being displayed on the admin widget page.<br />USAGE: Edit the wp-admin.css file in the plugin folder (NOT the admin core folder!!) with the css changes you want. This plugin simply applies a css file to over-ride the current core admin style sheet.
Author: Peter Easton
Version: 1.0
Author URI: http://byfordwa.com
*/

function my_admin_head() {
        echo '<link rel="stylesheet" type="text/css" href="' .plugins_url('wp-admin.css', __FILE__). '">';
}

add_action('admin_head', 'my_admin_head');

?>