I use wool nappy covers overnight. Any leaking gets sucked up by the wool ( wool can absorb 30% of its weight in fluid) and evaporates while the baby is wearing it. Wool nappy covers cost about $45 but at her age this would last you through till baby is out of night nappies unlike buying more nappies for the next 12-18mths. To clean it just pop it in the sun, no need to wash as the wool naturally sanitises itself and the sun helps that too!