Thanks guys. I digged around and found out that there's an option where fb will send an sms to your mobile in order for you to log in at a new device. That might help.
The hackers are all local. From my previous experience, here's what they will do once they manage to successfully hack into your account:
1) Learn about your friends/families (Common friends, their families, etc)
2) facebook chat them, or asking for their BBM PIN (BBM is still the dominant IM in Indo) or WhatsApp or Line or WeChat or whatever
3) Pretend to be me
4) Ask them about their friends/families etc. This is done to reassure the target that it really is me who is messaging them.
5) Tell them I'm in a emergency and cannot make a phone call
6) That I need money very urgently but my bank account is not working bla bla bla and they have to transfer it to the scammer's account
7) Voila
That was what happened to me about 1-2 years ago. From about 20 targets that they chose, 1 of them, my brother-in-law was kind and gullible enough to fall prey to it. It cost him US$4000. He told me that he managed to recoup the money back from the bank/police but I highly doubt it. I think he was just being nice and didn't want me to feel bad about it.
So, be careful guys.