Save directly to specific folder

I'm using some PDF library to print report to pdf. When I press print i open my pdf but i want to store all printed documents on specific folder?
There is my source code:
...

Response.AddHeader("Content-Disposition", "attachment; filename=Racun.pdf")
Response.ContentType = "application/pdf"

Dim pdf As PDFDocument = r.Ispis()

pdf.Save()
Response.End()
...

...