Welcome to Seoul. I hope that korea4expats.com has been of some help to you as you prepare to come to Seoul.
You will find a number of groups you can join here:
http://www.korea4expats.com/article-community-groups-clubs-seoul.htmlTwo that I would suggest you contact are the Moms and Kids group and SIWA (Seoul International Women's Association). Through these two groups you will likely connect with moms with children the same age as yours as well as some from Malaysia and/or who have lived in the same countries as you have.
Keep an eye on our What's Going On section for activities for children - some may be in or near where you will be living. These are another way to connect with other mothers.
As you prepare for you move, we hope that the information in our Moving to Korea as well as the other sections will be of help.