I will be staying from 11-8/2013 to 11/11/2013 8pm flight departure somewhere in Ho Chi Minh City (not yet booked).

I need reliable internet on 11/11/2013 at 10AM.

Where should I stay to ensure this happens via wifi? Should I buy a data card sim?

It is an absolute must, and if I can't be on the internet at that time to a USA VPN for two hours I will need to leave the country early.