there's loads to do in sth america in feb and march. mountaineering, long rock routes short rock routes etc etc. dont know your experience so ill give some general info. few ideas for you.
torres del paine - some excelllent stuff there. logistically a bit more difficult. need permits and good to have partner organised b4hand. worthwhile going in there for look around anyway. mate of mine managed to cruise in and find a partner and poach and ascent of the central tower a few years back.
fitzroy area - lots of stuff to do here. its mostly quite big and serious stuff here. once again good to have parter sorted b4hand but possible to find partners here. great bouldering 2 minutes from town too. no permits.
lots of climbing around bariloche - great alpine rock around refugio frey. just need approach shoes. lots of other stuff around bariloche too. sport climbing too.
can also go and do an ascent of tronodor near bariloche. snow and ice peak.
further north lots of 6000m peaks in chile, argenitina and bolivia and peru. slightly out of season for bolivia and peru but still possible to do stuff.