the ğ is a Turkish letter (\u011F LATIN SMALL LETTER G WITH BREVE). You would need a modernized Frutiger version which includes that glyph but I am not sure there is one available. Some fonts are not available with extended Latin, Cyrillic and Greek glyphs (also know as the WGL – Windows Glyph List, see wikipedia.org). So your other option is to create it from g and ˘ (breve), characters which have been available at least on Mac for years so I guess even on Windows you can access them. Well, just copy and paste from this.