I have two pages, buyerpage.php (on my server) and paymentgw.asp (on my merchant payment gateway)

The first one is intended to take the credit card info of my clients, and send it directly via POST METHOD to paymentgw.asp (on HTTPS adress) using LIBCURL FUNCTIONS (as we know to send post data directly to server)
https://www.paymentgw.com/paymentgw.asp

Then this page returns a redirect response to my buyerpage.php (on HTTP) but adding an URL STRING VARIABLE:
ex:
http://www.myserver.com/buyerpage.php?VAR=APPROVED
or
http://www.myserver.com/buyerpage.php?VAR=DECLINED

QUESTION:
HOW COULD I TAKE THAT URL STRING FROM THE RESPONSE OF THE GATEWAY SERVER PAGE USING LIBCURL FUNCTIONS???

You can see an explanatory image as attachment here
http://mochikit.sc31.info/urlstringquestion.gif
THANKS IN ADVANCE!!!

Saludos desde PERU!

JR