I'm assuming you are already pregnant since you bought a package from your gynea. Most private insurance companies have a mandatory waiting period of 10 months or so before they cover expenses but I heard AXA has some sort of special insurance for complications that you can get when already pregnant.
As for your little one - your husband should check with his company if his insurance is available for dependents. If so, you should make sure he registrers your child within the first two weeks. If not, there is a special deal we got offered in Mt. E for the first 6 months for special price and it can be further extended.
Not sure what your budget is, I think NTUC offers low cost medical insurance but you'd need to research it.
Hope this helps - best of luck!