if you want to continue using 0-255 can create a function for this as the following example.
function setFillColor2(...)
local object,r,b,g=...
object:setFillColor( r/255, b/255,g/255)
end
circle1 = display.newCircle(150,250, 50 )
setFillColor2(circle1,23,255,12)