well, I got the solution.
what I did is so much simple, I used javascript to read values from control inside the IFRAME, saved them in a hidden filed, then from code behind file, I get them from hidden field and set them to their relative place.
this is what I used
Javascript:
var IFrame = document.getElementById("IFrameIDHere");
var Values = "";
Values += IFrame.contentDocument.getElementById("control_1").value + ",";
Values += IFrame.contentDocument.getElementById("control_2").value + ",";
Values += IFrame.contentDocument.getElementById("control_3").value + ",";
.
.
.
.
Values += IFrame.contentDocument.getElementById("control_n").value + ",";
document.getElementById("HiddenFieldID").value = Value;
after that, I did this from code behind file. (C#)
string[] Values = HiddenFieldID.Text.ToString().Split(',');
now, I used values from this array and did my task..