How Do I Convert From Xml.Gz To Dataset

public void FnSearchTorix()
       {
       string AuthResponse = new WebClient().DownloadString("http://www.hotelspro.com/xf_3.0/downloads/KT6193hotellist.xml.gz");
        DataSet DSAuth = new DataSet();
       DSAuth = ConvertXMLToDataSet(AuthResponse);
       DataTable dt = new DataTable();
       dt = DSAuth.Tables[0];
       }


       private DataSet ConvertXMLToDataSet(string xmlData)
       {
           String xmlRes = String.Empty;
           FileStream stream = new FileStream(xmlData, FileMode.Create);

           GZipStream responseStream = new GZipStream(stream, CompressionMode.Decompress);
           responseStream.Flush();
           StreamReader sr = new StreamReader(responseStream, System.Text.Encoding.Default);
           System.Text.StringBuilder sbOutput = new System.Text.StringBuilder();
           char[] buffer = new char[4096];
           int r;
           while ((r = sr.Read(buffer, 0, buffer.Length)) > 0)
               sbOutput.Append(buffer, 0, r);
           xmlRes = sbOutput.ToString();
           DataSet xmlDS = new DataSet();
           StringReader stream1 = null;
           XmlTextReader reader1 = null;
           try
           {
               stream1 = new StringReader(xmlRes);
               // Load the XmlTextReader from the stream
               reader1 = new XmlTextReader(stream);
               xmlDS.ReadXml(reader1);
               return xmlDS;
           }
           catch
           {
               return null;
           }
           finally
           {
               if (reader1 != null) reader1.Close();
           }
       }