I don't think this question is well defined enough to be meaningful. In terms of how quickly it can carry out complex calculations, low end modern laptops leave your brain in the dust. What few functions the brain can still claim any advantage on are the result of dedicated wetware and our ability to learn and thereby specialize software. Computers will get there, but it's not really a Moore's Law problem.
The title of this article should not be misconstrued to mean that the brain is a more powerful computation device, only that it is more complicated.
I don't think this question is well defined enough to be meaningful.
You can certainly get closer than asserting that, e.g., a hand calculator is more powerful than a human brain because it can do 7 digit long division almost instantly.
At some point, we'll have computers powerful enough to run a working simulation of a human brain. Shortly before that, there will be a point when computers of that sort are "as powerful as a human brain", though we might not realize it when that happens if the software lags.
