The IMF has new purchasing power parity forecasts out to 2016 and new nominal GDP forecasts out to 2016. The IMF does not seem to make any attempt to have accurate currency forecasts for its nominal exchange rate forecasts.
Brazil and Russia are forecasted to pass France, Italy and the UK. Brazil will be the 5th largest national economy and Russia will be the 6th largest. India is forecast to be ahead of Italy but behind France.
The World will have a $100 trillion economy on a PPP basis in about 2015 and on a nominal GDP basis in 2018.