Wordpress Theme Switcher plugin redirect modification

Hello,

I would like to modify the Theme Switcher Plugin for Wordpress (http://dev.wp-plugins.org/wiki/ThemeSwitcher). When I currently request the page to switch the theme (for example: mydomain.com/?wptheme=My+Theme) I'm redirected to the index.php, but instead I would like to redirect back to the page where I was before (for example: mydomain.com/?p=15)

Here is the code which is redirecting the page:

function ts_set_theme_cookie() {
	$expire = time() + 30000000;
	if (!empty($_GET["wptheme"])) {
		setcookie("wptheme" . COOKIEHASH,
							stripslashes($_GET["wptheme"]),
							$expire,
							COOKIEPATH
							);

		$redirect = get_settings('home').'/';

		if (function_exists('wp_redirect'))
			wp_redirect($redirect);
		else
			header("Location: ". $redirect);

		exit;
	}
}

PHP:

I've tried to change the $redirect variable to $_SERVER['REQUEST_URI'] but it doesn't worked. Any recommendations how to do it? I will really appreciate it.

Thanks,
Erik