Storing UserID - Where?

Hi all,
I'm using Forms authentication and after the user logs in I need to capture the users 'RegID' and keep it for the length of the cookie (60 minutes in this case).
What is the best way to hold this data? at the moment I'm sticking it into a session, but if the user closes the browser the session data is lost. Is it possible to store it in the cookie and retrieve it? if so, how?
Thanks Melt
protected void LoginAction_Click(object sender, EventArgs e)
    {

        Page.Validate();
        if (!Page.IsValid) return;
             
        // Initialize FormsAuthentication (reads the configuration and gets
        // the cookie values and encryption keys for the give ...