overfilling the oil will make it leak more obviously but mine and a few other R32s I know leak from the rocker cover, its fairly common. Mine leaks most from the rear passenger side.
I had the same problem on my Silvia and ended up using a high temp good quality sealant and it fixed it nicely for the 2 years I had the car. I will do the same with the R32.
As for the idle. Ever since I imported mine the auto choke doesn't kick in on its own, if you start it from cold it stutters and dies, I have to help it with the throttle. Its something to do with the throttle body bypass being dirty. Again, something I will do when I can be bothered.
The warning light could be a major problem so if its staying on I'd advise not driving it. What light is it? the one on the oil pressure guage or the one at the bottom?