firstly congrats on your move. Singapore is a fantastic place for families (I personally believe). We also debated bw areas and dwelling types and I have to say unless you have a big budget to get a house with pool, condos
can be a fantastic place for families. Access to a playground, pool, squash etc is great. We use the pool and playground every day. Not all apts are large though and it will depend what you are used to. I suggest seeing a range of dwellings (condo vs house vs cluster house) to see what the right balance of space and facilities is for you.
If moving to a condo
, take a look around to see whether there's lots of expats...depending on your preferences that could be a good or bad thing. Our condo has all nationalities but we tend to gravitate toward other aussies, english, europeans and americans. Our condo social circle has become very important to us an our kids.
If you get a house with no pool, you may want to consider joining a 'country club'. If you can get in, several offer $4K per year membership.
We selected River Valley to live because of the proximity to cafes / shops and the city (for a short commute). The AU school is about a 10-15m drive from here although the school bus will take longer.
In addition to East Cost, lots of expats live around Holland Village, Tanglin, Bukit Timah which are all lovely but further from the city (longer commute) and the AU school (I think).
In terms of houses, unless you live out or pay rent > $15K per month (although it;s coming down!!) I get the sense that most of them have a courtyard sized outdoor space unless you have a good budget.
If you select to put the kids on the school bus (common practice since they come to your door), the commute isn't direct so it's always worth checking with the bus companies how long the commute is if you live x) vs y). That;'s because kids are picked up all over (not all on the same bus though!!).
Side issue but check the AU school doesn't have a waitlist.
So, with housing, invest several days getting driven around to different areas and get a feel for access to parks, playgrounds, cafes (etc, whatever is important to you) kids activities (like gym, swimming etc). See some different housing options (condo vs house). Think about what's important. For us for instance, although cabs are cheap, we wanted walking access to cafes/wine bars/shops/park.
We live in Aspen heights and penthouse apartments are 2600 square feet (5 br) so it would fit your fam ily no prob. I would normally recommend it but our pool is due for a refurbishment and it will be closed for 6 months, which, after what I told you re: how much we use it) is a massive pain.
Anyway, one last tip is rents really falling because of the recession. Some agents and landlords are in denial about this because of rents being high for some time and also because this things called 'saving face' where they do not want to cave in negotiations. Be prepared to bargain hard or walk away. For instance, if it's listed for $10K, offer 7-8K and see where it goes. There's plenty of stock so don't be fooled into signing.
Also, if you aren't certain about your choice, ask for a 1 year lease (most are 2). Lastly, and most importantly, make sure your leave (if 2 year) includes a 'diplomatic clause' that allows you to get out of it if your/your husband is ransfered away/loses job etc.
Hope this helps. Best of luck.