A nonprofit giant of the South Bronx is taking the children it serves to new heights with a sprawling school development slated to open in September 2013. Women’s Housing and Economic Development Corp. is combining two areas it knows best — child-care and affordable housing — when it breaks ground on a 355,000-square-foot complex hosting low-income housing and the WHEDco Bard Academy Charter School. The City Council has appropriated $2.5 million towards construction of the complex, which has been planned for two years. WHEDco is partnering with Bard College, which already has a presence in competitive city high schools, to offer a rigorous liberal arts program with an emphasis on the arts. The campus will include a Bronx Music Heritage Center for education and performances.