$5k/month is perfectly good to live on here. Rents are tumbling, taxes are low and as long a s you like 'local' food (being malay, indian, chinese ...). Sadly some of my felloow expats from caucasian countries compalin of the cost of living because they mostly dine in western resaturants.
Live a 'normal' lifestyle here and your income is ample.
Have fun and welcome to Singapore