save listview data to same excel file but different sheet

[sigridish]

hi everybody! i already know how to save in excel using openfiledialog. but what i want to happen is that when i save another file, i want it to be saved in my existing file but in a different sheet. can you guys help me?

this is my code for saving

Public Sub saveExcelFile(ByVal FileName As String)
        Dim xls As New Excel.Application
        Dim sheet As Excel.Worksheet
        Dim i As Integer
        xls.Workbooks.Add()
        sheet = xls.ActiveWorkbook.ActiveSheet
        Dim row As Integer = 1
        Dim col As Integer = 1
        For Each item As ListViewItem In ListView1.Items
            For i = 0 To item.SubItems.Count - 1
                sheet.Cells(row, col) = item.SubItems(i).Text
                col = col + 1
            Next
            row += 1
            col = 1
        Next
        xls.ActiveWorkbook.SaveAs(FileName)
        xls.Workbooks.Close()
        xls.Quit()
    End Sub

 Private Sub btnsave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnsave.Click
        Dim saveFileDialog1 As New SaveFileDialog
        saveFileDialog1.Filter = "Excel File|*.xlsx"
        saveFileDialog1.Title = "Save an Excel File"
        saveFileDialog1.ShowDialog()
        If saveFileDialog1.FileName <> "" Then
            saveExcelFile(saveFileDialog1.FileName)
        End If
        MessageBox.Show("Record Saved!")
    End Sub