Which is the equivalent processing of human brain in terms of computer processing?
Here is what we know for sure. The largest neuronal network simulation to date was achieved using the K Japanese supercomputer (see the Top500) during summer 2013, a few months ago.

Using the open-source software NEST, the scientists simulated a network consisting of 1.73 billion nerve cells connected by 10.4 trillion synapses. To realize this feat, the program recruited 82,944 processors of the K Computer and used 1 petabyte of memory. The process took 40 minutes, to complete the simulation of 1 second of neuronal network activity in real, biological, time.
Although the simulated network is huge, it only represents 1% of the neuronal network in the brain. 

K is a peta-scale supercomputer, so, we need an exa-scale machine to completely simulate the whole human brain. These machines will be (probably) available between 2017-2020.