Use GPU-Z to see how hard your GPU is being used
Unfortunately you have dual core + Hyperthreading so four cores virtually but only two in reality.
60% of four cores means that your two real cores hae reached their limit already
The new patch (beta) is givig good use to Quad cores, unfortunately you can not benefit from it.
You need to start experimenting.
And forget London for the time being... this will be fun in a few years time, when the HW wll be available for it.