add my own created widget code in wordpress

i created my own widget code by php programe for wordpress…and i want to add that widget into widget panel..so if i want to show on that widget in my widget panel where i add(means which file in wordpress) my widget code…?

<?php

add_action( 'widgets_init', 'my_widget' );


function my_widget() {
    register_widget( 'MY_Widget' );
}

class MY_Widget extends WP_Widget {

    function MY_Widget() {
        $widget_ops = array( 'classname' => 'example', 'description' => __('A widget that displays the authors name ', 'example') );

        $control_ops = array( 'width' => 300, 'height' => 350, 'id_base' => 'example-widget' );

        $this->WP_Widget( 'example-widget', __('Example Widget', 'example'), $widget_ops, $control_ops );
    }

    function widget( $args, $instance ) {
        extract( $args );

        //Our variables from the widget settings.
        $title = apply_filters('widget_title', $instance['title'] );
        $name = $instance['name'];
        $show_info = isset( $instance['show_info'] ) ? $instance['show_info'] : false;

        echo $before_widget;

        // Display the widget title 
        if ( $title )
            echo $before_title . $title . $after_title;

        //Display the name 
        if ( $name )
            printf( '<p>' . __('Hey their Sailor! My name is %1$s.', 'example') . '</p>', $name );


        if ( $show_info )
            printf( $name );


        echo $after_widget;
    }

    //Update the widget 

    function update( $new_instance, $old_instance ) {
        $instance = $old_instance;

        //Strip tags from title and name to remove HTML 
        $instance['title'] = strip_tags( $new_instance['title'] );
        $instance['name'] = strip_tags( $new_instance['name'] );
        $instance['show_info'] = $new_instance['show_info'];

        return $instance;
    }


    function form( $instance ) {

        //Set up some default widget settings.
        $defaults = array( 'title' => __('Example', 'example'), 'name' => __('Bilal Shaheen', 'example'), 'show_info' => true );
        $instance = wp_parse_args( (array) $instance, $defaults ); ?>

        //Widget Title: Text Input.
        <p>
            <label for="<?php echo $this->get_field_id( 'title' ); ?>"><?php _e('Title:', 'example'); ?></label>
            <input id="<?php echo $this->get_field_id( 'title' ); ?>" name="<?php echo $this->get_field_name( 'title' ); ?>" value="<?php echo $instance['title']; ?>" style="width:100%;" />
        </p>

        //Text Input.
        <p>
            <label for="<?php echo $this->get_field_id( 'name' ); ?>"><?php _e('Your Name:', 'example'); ?></label>
            <input id="<?php echo $this->get_field_id( 'name' ); ?>" name="<?php echo $this->get_field_name( 'name' ); ?>" value="<?php echo $instance['name']; ?>" style="width:100%;" />
        </p>


        //Checkbox.
        <p>
            <input class="checkbox" type="checkbox" <?php checked( $instance['show_info'], true ); ?> id="<?php echo $this->get_field_id( 'show_info' ); ?>" name="<?php echo $this->get_field_name( 'show_info' ); ?>" /> 
            <label for="<?php echo $this->get_field_id( 'show_info' ); ?>"><?php _e('Display info publicly?', 'example'); ?></label>
        </p>

    <?php
    }
}

?>