FontFactory limitations, how do i get an underline or more font options

Question

Hi I am declaring the following variables - which i use later in my code when writing out to PDF. When I drop down FontFactory intellisense though I get hardly any options, only TIMES and HELVETICA variations plus bold etc, how would I get Arial underline for example? Is their an additional using clause or something?

    Font font_small = FontFactory.GetFont("Arial", 8);
    Font font_medium = FontFactory.GetFont("Arial", 11);
    Font font_large = FontFactory.GetFont(FontFactory.HELVETICA_BOLD, 13, Color.GRAY);
    Font font_title = FontFactory.GetFont("Arial", 13);

thanks in advance JOhn