如何取得response.redirect 中的转身网址??

下面是一个取得网页的源代码,但当网页是一个转向时(response.redirect),怎样才能取得response.redirect 后面的网址呢??? 
请高手指教：
<%@Page Language="C#" Debug="true"%> 
<%@Import NameSpace="System.Net"%> 
<%@Import NameSpace="System.IO"%> 
<script language="C#" runat="Server"> 
string sException=null; 
public string GetHttpData(string sUrl){ 
        string sRslt=null; 
      string urls; 
        WebResponse oWebRps=null; 
        WebRequest oWebRqst=WebRequest.Create(sUrl); 
        oWebRqst.Timeout=50000; 
        try{ 
                oWebRps=oWebRqst.GetResponse(); 
             
        } 
        catch(WebException e){ 
                sException=e.Message.ToString(); 
        } 
        catch(Exception e){ 
                sException=e.ToString(); 
        } 
        finally{ 
                if(oWebRps!=null){ 
                        StreamReader oStreamRd=new StreamReader(oWebRps.GetResponseStream(),System.Text.Encoding.GetEncoding("GB2312")); 
                        sRslt=oStreamRd.ReadToEnd(); 
                        oStreamRd.Close(); 
                        oWebRps.Close(); 
                } 
        } 
        return sRslt; 
} 
</script> 
<% 
TimeSpan oStartTime=DateTime.Now.TimeOfDay; 
string s=HttpUtility.HtmlEncode(GetHttpData("http://test.fzclx.com/caixi/test.asp")).Replace("\n","\n<br>"); 
Response.Write(s); 
Response.Write("<br><br>\r\n执行时间：" + DateTime.Now.TimeOfDay.Subtract(oStartTime).TotalMilliseconds.ToString() + " 毫秒"); 
%>