Export Special Characters to PDF using iTextSharp in ASP.Net

Hi all, by using below url i exported special characters like ∩, ∑, ∫, ∆ gridview data to pdf.

http://www.aspsnippets.com/Articles/Export-ASPNet-GridView-Arabic-Persian-or-Urdu-Language-Characters-to-PDF-using-iTextSharp.aspx

my requirement is

some special characters like ∈ not exported AND

instead of

BaseFont bf = BaseFont.CreateFont(Environment.GetEnvironmentVariable("windir") + @"\fonts\Arial.ttf", BaseFont.IDENTITY_H, true);

i want to use(my requirement)

BaseFont bf = BaseFont.CreateFont(Environment.GetEnvironmentVariable("windir") + @"\fonts\Times New Roman.ttf", BaseFont.IDENTITY_H, true);

but at runtime i get the error "Times-New-Roman" not found, but in my "windir" i have "Times New Roman.ttf" in font folder.

if any body understand my problem please help me.

Thanks in Advance