1999 i/o from Colombia

Greetings from Colombia, I have a 1999 i/o (SOHC 16v). in my country there are no more than 10 of these cars. Get some spare parts is very difficult. I need a set of pistons. the part number is MD350312,  I asked to anayima but they dont have them. The engine number is 4g93kj9870, is there any alternative to these pistons? or where can i find them? Thanks for your help ...