The pressure regulator you need is the same technology you breathe through Reducing Valves when you dive (you really don't want air at 230 bar in your lungs).  You might be able to modify one of those that you already have to give you 2 bar instead of 0.1 bar.
Regardless of where you get the regulator, you need to make sure that your air source is either absolutely dry or you have some sort of filter upstream of your regulator.  I fed an air brush moist air through a regulator once and three ugly things happened pretty quickly: (1) the Joule-Thompson cooling caused some water vapor to condense and the water spots ruined what I was painting; (2) the regulator froze and started spitting air as the dP broke the freeze and then refroze (globbing paint out the tip); and (3) a rubber O-ring in the regulator failed and I threw the damn thing away.  Diving air is certified dry and oil-free so that source should be ok, you intermediate-pressure source needs to be checked carefully.

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