I recognise that wheel style, but cant put my finger on what they are, definitely not Nismo though. So think you will struggle to find a replacement in the right width, size and offset, whats wrong with the one that needs replacement?
Brakes pads from pretty much anywhere, just make sure as said you get the jdm brake pads, NOT brembo ones as they are a completely different caliper, take a pad to euro car parts and reg number and they will have them on the shelf.