Data Reader Question

Hi Guys,
I have a quick question about DataReader, I have a function called "ExportTotal" i am calling this function from another function. what it does is it will put the Total for each Network in the Line 34. Right now what it is doing is It is putting the First Networktotal,2ndNetwork total,3rdNetwork total....... in the line 34. what i want is if the control comes to first network then it has to put only 1st network total and for the 2nd network only 2nd network total and so on. Please see my function below. Can you guys tell me what i am doing wrong?
Thx
Private Function exporttotal() As String
Dim sql As String
Dim dbFunctions As New DatabaseUtilities
Dim tempinvoicetotal As String
'Dim rateactuals As String
Dim filetext As String
Dim tempclientname As String
Dim strconn As String
Dim prev_network As String = ""
Dim current_network As String = ""

strconn = CONNECTIONSTRING



sql = "SELECT CAST(SUM(tblSpot.rateActual) AS int(4)) AS Rateactuals, SUM(tblSpot.rateActual * 0.85) AS netrate, SUM(tblSpot.rateActual * 0.15) AS commrate,TBLCLIENT.CLIENTNAME " & _

"FROM tblSpot INNER JOIN tblContract ON tblSpot.fkContract = tblContract.pkid INNER JOIN " & _
" tblClient ON tblContract.fkClient = tblClient.pkid WHERE tblSpot.fkContractType = 'UNWIRED' AND " & _
"fkInvoiceNumber = '" & Me.txtinvoicenumber.Text & "' GROUP BY TBLCLIENT.CLIENTNAME"

Dim myConn As New SqlConnection(CONNECTIONSTRING)
Dim myCommand As New SqlCommand(sql, myConn)
myConn.Open()
Dim dbreader As SqlDataReader = myCommand.ExecuteReader()
While dbreader.Read()

Try

Dim Rateactuals As String
If dbreader("Rateactuals") Is DBNull.Value Then
Rateactuals = ""
Else
Rateactuals = dbreader("Rateactuals")
tempinvoicetotal = Rateactuals
End If

Dim clientname As String
If dbreader("clientname") Is DBNull.Value Then
clientname = ""
Else
clientname = dbreader("clientname")
tempclientname = clientname
End If


If prev_network = "" Then

filetext = filetext & vbCr & "34;;" & tempinvoicetotal & "00" & ";"

Session("EDIExport4") = filetext
prev_network = tempclientname
Else
current_network = tempclientname
If prev_network <> current_network Then
filetext = filetext & vbCr & "34;;" & tempinvoicetotal & "00" & ";"

Session("EDIExport4") = filetext
prev_network = tempclientname

Else

End If
End If

Catch SqlEx As SqlClient.SqlException
Session("Error") = SqlEx.Message.ToString
Response.Redirect("Error.aspx?Form=" & Request.Path)
Catch Ex As System.Exception
Session("Error") = Ex.Message.ToString
Response.Redirect("Error.aspx?Form=" & Request.Path)
End Try
dbFunctions = Nothing
End While
myConn.Close()
End Function