export to excel with creating 2 worksheets in vb.net

Why not use the Excel.Application object to create a workbook with two sheets and fill them in.

From a simple name and address database export:

Dim Excel As Object = CreateObject("Excel.Application")
With Excel
'
' New Work Book With Two Sheets
'
.SheetsInNewWorkbook = 2
.Workbooks.Add()
.Worksheets(1).Select()
'
' Write in the Header Row
'
.cells(1, 1).value = "Title"
.cells(1, 2).value = "Name"
.cells(1, 3).value = "Address1"
.cells(1, 4).value = "Address2"
.cells(1, 5).value = "Address3"
.cells(1, 6).value = "Town"
.cells(1, 7).value = "County"
.cells(1, 8).value = "Postcode"
.cells(1, 9).value = "Country"
.cells(1, 9).EntireRow.Font.Bold = True
'
' Fil in all the Data Rows from the Current View
'
i = 2

Do While rd.Read
.Cells(i, 1).Value = rd("title")
.Cells(i, 2).Value = rd("name")
.Cells(i, 3).Value = rd("addr1")
.Cells(i, 4).Value = rd("addr2")
.Cells(i, 5).Value = rd("addr3")
.Cells(i, 6).Value = rd("town")
.Cells(i, 7).Value = rd("county")
.Cells(i, 8).Value = rd("postcode")
.Cells(i, 9).Value = rd("countries_name")

i += 1
Loop
rd.Close()

.Columns("A:I").EntireColumn.AutoFit()

Excel.Visible = True
End With

System.Runtime.InteropServices.Marshal.ReleaseComObject(Excel)
Excel = Nothing

Obviously when you want to fill in sheet 2 use Worksheets(2).Select() or use Worksheets(2).Cells(x,y).value = ...