International schools in Kuala Lumpur are expensive, especially those using the American ad British curriculum, and could cost from USD 3,000 to 15,000 per annum. Rental of a decent 2-bedroom apartment in KL costs RM 2,500 onwards and cars aren't cheap. I definitely suggest for you to approach the HR department of your company to provide for your child's education and apartment. With that taken care of, you can live comfortably on RM10,000 with your wife and kid in KL.