the order form should be separate from the login page.
we have a tutorial here for creating an order history page:
http://www.webassist.com/tutorials/Create-an-order-history-page
that is the basis for being able to track who placed orders.
to track the number of times a person logs in, you would need to add an insert behavior to record the login. one of our forum members wrote a tutorla here for that:
http://www.webassist.com/tutorials/Show-online-users