For the redirect.. I don't believe you can. And if you could, it would take a good bit of work. You should see Javascript for that. Using setTimeOut() and location.href. Say something simular to
setTimeout("location.href('URL')",15000);.
For passing variables through a URL I'm assuming you're wanting to read them? You just need to use $_GET['var'] and then do something with it..
Say something like..
$var = $_GET['var'];
if (!$var) {
echo "Variable is unset.";
} else {
print $var;
}