PAGE SETUP in Export GridView to Excel PLEASE HELP!!

[GAiXz]

how do i set the format for that after click the button from gridview to excel file??

what's the code for this format??

in page tab:
orientation = landscape
scaling = 30%
paper size = A3
print quality = 300dpi

in margings tab:
width = 0.25
top = 0.25
height = 0.25
bottom = 0.25
left = 0.25
right = 0.25

center on page:
vertical = check

i'm using this code....

Response.Clear()
        Response.AddHeader("content-disposition", "attachment; filename=File.xls")
        Response.Charset = ""
        Response.ContentType = "application/vnd.xls"
        Dim stringWrite As New System.IO.StringWriter()
        Dim htmlWrite As System.Web.UI.HtmlTextWriter = New HtmlTextWriter(stringWrite)
        GridView1.RenderControl(htmlWrite)
        Response.Write(stringWrite.ToString())
        Response.[End]()