Never mind, found it!! I typed in 'Indonesian carmanufacturer' into Google and this picture was on the first page ... Same car, I think?
It's a Gea Inka or 'Gea' made by 'PT Inka', wich stands for 'PT Industri Kereta Api'. The prototype was made in 2008 and it uses a 650cc engine. According to their website, they're used to making trains (?). I've never heard of it ...