Where i can get amiga os 3.9 or newer for pc

[Colani1200]

You can buy OS 3.9, e.g. at Vesalia (http://www.vesalia.de) or (http://www.amigakit.com), but it can not be installed natively on your PC. You can run it in an emulator though (WinUAE or E-UAE).

If you want to install a Amiga-like OS on your PC, I suggest you take a look at Icaros Desktop: http://www.icarosdesktop.org