Hello:
The scope of an include is limited to the page in which it is called. It is called inline, and in that regards is similar to the <img> tag: Where it is called, it will be displayed, or perform the actions within the script.
However, one page does not know the values of another page's variable values unless you pass those values specifically.
You have a few options to do so:
Via the $_GET[]; (You can pass values via the query string or a form using the GET method)
Via the $_POST[]; (You pass values using a form with the method of POST)
Via the $_SESSION[]; (You start a session and save values in specific session vars)
Via the $_COOKIE[]; (Create some cookies)
All of these are called GLOBAL arrays, and can be used to help you. If the information is not posted from a form, you may consider using SESSION here.
Check out: http://www.php.net/session_start
HTH.