Input&Output Proplem

I want to change links like this

"http://www.google.com/?d=GVOMXHQ2"

to

"http://www.google.com/mgr_dl.php?d=GVOMXHQ2" but its dont convert the Url to it.

Script need only to read this

"/?d=" changed input to

"mgr_dl.php?d="

Anybody can help ?

HTML Code:

#include <IE.au3>

$gui = GUICreate("Internet", 800, 600, 195, 127)
$String = GUICtrlCreateInput("http://www.google.com/?d=GVOMXHQ2", 5, 355, 440, 21)
$GoogleString = "http://www.google.com/"
$myVar = StringRight($String, 8)
$Result = $GoogleString & "mgr_dl.php?d=" & $myVar
$button_url = GUICtrlCreateButton("Get It", 456, 352, 129, 25, 0)
$oIE = _IECreateEmbedded()
$oIE_ctrl = GUICtrlCreateObj($oIE, 0, 0, 800, 300)

GUISetState(@SW_SHOW)

_IENavigate($oIE, "http://www.google.com/?") 



While 1
    $nMsg = GUIGetMsg()
    
    Switch $nMsg
        Case -3
            Exit
        Case $String
            _IENavigate($oIE,$Result)
    EndSwitch
WEnd