Inspirational singer Amy Grant, 39, and her husband, country singer Vince Gill, 43, are expecting a baby, a rep for Gill told the Associated Press yesterday. "She's due at the end of March," said Allison Auerbach. The Nashville-based Gills were married on March 10. She has three children with Christian singer Gary Chapman, whom she divorced in 1999. Gill and his former wife, country singer Janis Gill, have a daughter.