I bought one of these from a neighbourhood store that sells mops and buckets and everything else! It cost me about $10 and it screwed on very easily, I actually bought two and to feed 3 devices (fridge freezer, dishwasher and washing machine) from the same tap
Also, you may need to get a 'y' pipe for your waste, I got a 't' pipe and a 90 degree bend stuck together to create two vertical inputs, I bought it in a plumbing supplies shop on Joo Chiat road - Dishwasher and washing machine both need a waste - it only cost me $2-$3 in total, the guy there even gave me a hug included! I think he wanted to see if his arms would go around me.
so $15 willl see you right and save you an expensive plumber visit. (and maybe get a cuddle from a big Malay chap if you are lucky)
nut2