I'm pretty sure Jobcase only has US jobs right now, so you might need to check a different website for those opportunities. That must be rough looking for a job in another country without knowing! Unfortunately I also do not know what is required to work in Canada, London, or Dubai when you are from elsewhere. Are there any offices anywhere or friends you can ask about how to get started?

Are you near Lagos? You could check out this website for how to get a Canadian visa: http://www.cic.gc.ca/english/information/offices/missions/lagos.asp