I am unable to retain state of the page.

I am working on a popup window with login_redirection, which pops up based on a condition in the OG Module.

I am calling the following JavaScript from the OG module after verifying a condition.

pop = window.open ("/pop.php?name=$name," User Info" , "location=0,status=0,scrollbars=0,resizable=disallow,width=500,height=580,screenX=0,screenY=100,left=250,top=100");

I am able to get the popup window but I am unabe to get the user details on the popup page.

ex:
global $user;
$user->uid (Displays no information).

also when i click a button and do a post back to a different node in the site. The user session / cookie expires and logs me out..

Is there a way I can preserve the state, without logging of the site?

Thanks