March 20 (Reuters) - Canadian main stock index futures pointed to a higher open as investors shifted their focus from Cyprus's financial woes to the U.S. Federal Reserve's policy meeting, where the central bank is expected to sustain its $85 billion monthly bond-buying stimulus despite improving economic data. TOP STORIES * Cyprus's finance minister pleaded with Russia for help to avert a financial meltdown after the island's parliament rejected the terms of a European bailout, raising th