I want to print my datagridview, but in merged table inside print preview

Question

I have a datagridview like this, as we can see there's total amount column. I want to print the datagridview, and make sum of total column at the end of the row in merged column. what should I do to make it work?

I am expecting the result must be like this and I had try this

Using f As Font = New Font(cobacoba.dgv2.Font.FontFamily, cobacoba.dgv2.Font.Size)
    Using br As New SolidBrush(Color.Black)
        'draw the header
        Dim CellLeftPos As Integer = 50
        For col = 0 To cobacoba.dgv2.ColumnCount - 1
            Dim CellValue As String = cobacoba.dgv2.Columns(col).HeaderText
            Dim CellWidth = cobacoba.dgv2.Columns(col).Width + 50

            e.Graphics.FillRectangle(Brushes.LightGray, CellLeftPos, CellTopPos, CellWidth, CellHeight)
            e.Graphics.DrawString(CellValue, f, br, CellLeftPos + offset, CellTopPos + offset)
            e.Graphics.DrawRectangle(Pens.Black, CellLeftPos, CellTopPos, CellWidth, CellHeight)

            CellLeftPos += CellWidth
        Next
        CellTopPos += CellHeight

        'draw the rows
        For Row = LastRow To cobacoba.dgv2.RowCount - 1
            CellLeftPos = 50
            CellHeight = cobacoba.dgv2.Rows(0).Height

            For Cell = 0 To cobacoba.dgv2.ColumnCount - 1
                Dim CellValue As String =     cobacoba.dgv2.Rows(Row).Cells(Cell).Value.ToString()
                Dim CellWidth = cobacoba.dgv2.Rows(Row).Cells(Cell).Size.Width + 50

                e.Graphics.DrawString(CellValue, f, br, CellLeftPos + offset, CellTopPos + offset)
                e.Graphics.DrawRectangle(Pens.Black, CellLeftPos, CellTopPos, CellWidth, CellHeight)
                CellLeftPos += CellWidth
            Next

            CellTopPos += cobacoba.dgv2.Rows(Row).Cells(0).Size.Height

            If CellTopPos > e.MarginBounds.Bottom - cobacoba.dgv2.Rows(Row).Cells(0).Size.Height Then
                e.HasMorePages = True
                LastRow = Row + 1
                Exit Sub
            End If
        Next
    End Using
End Using

but the result is what should I do?