A referendum date has been set in Brookfield for a vote on building a new elementary school. During a Town Meeting last night, residents agreed that a referendum should be held on March 5th.  With state grant money, the project to construct a building on the Huckleberry Hill campus, tear down that school and transfer Center School students into the new building, is pegged at $63.2 million.  A driveway, parking and ball fields would also be added.  The old Center School would be turned over to the town for municipal use.