I'd suggest to bring your child to places like Kaki Bukit Shun Li Ind Bldg to try out all the different car seats available before making your choice.
It can be quite an expensive buy, you should set a budget in mind. I saw a seat there that can be used from 6mths old to toddler stage which cost only S$300. Wanted to get that initially but my in law bought Mozar Bee for my girl instead.
Seems plasticky and hard, but the funny thing is, my girl loves it. She couldn't sleep without it, even at night.