Unfortanately Noma is one of those brands that you will probably not find any new parts for. The engine you will find all the parts you may need.
As far as the belts go, the best answer is to remove them and bring them in to a small engine shop. They will be able to measure them with a belt guide and match them up to some aftermarket belts without a problem.
You will want to use 5W-30 oil in that engine, and run a champion RJ19LM plug