You must use 64.43 g H₂O.
Balanced chemical equation: H₂O + CO₂ → H₂CO₃
Moles of CO₂ = 157.35 g CO₂ × (1 mol CO₂/44.01 g CO₂) = 3.5753 mol CO₂
Moles of H₂O = 3.5753 mol CO₂ × (1 mol H₂O/1 mol CO₂) = 3.5753 mol Fe
Mass of H₂O = 3.5753 mol H₂O × (18.02 g H₂O /1 mol H₂O) = 64.43 g H₂O