You can use the function do_shortcode()
for use shortcodes outside fomr default content. You can also parse this in your function, there get the output of your textfields, like the follow example for a custom field:
if ( get_post_meta( $post->ID, 'cfield', TRUE ) )
echo do_shortcode( get_post_meta( $post->ID, 'cfield', $single = TRUE ) );