Sydney to Taiwan

Hi. I'm a 39 year old native English speaker - white Australian living in Sydney.
I've got a degree in computer science and have worked for many years as a computer programmer, but I'm basically sick of it, and I quite like the idea of teaching English to non-natives. I'm married to a Chinese (mainland) and have spent 18 years communicating with her and have had practice explaining English things.

I'm thinking of going to China or Taiwan. I have already saved my money as a computer programmer, and so I no longer need to save money, I just need enough money to live on so that I don't have to draw down my savings.
My only real entertainment is the internet, so I don't particularly care where I live so long as I have internet access.
I have been doing some reading and it appears that a degree is not what employers want, they want a TEFL certificate. I have found one here:
http://www.teflcorp.com/os-dates-fees.htm
for which you can do online.
There's one here:
http://www.teachinternational.com/courses/index.php

which costs - (approx) which I can do in Sydney.

That's a huge price discrepancy. Is the first one bogus or the second one a ripoff?
Assuming the second one is the one I need, do I need the Foundation, the Certificate III or Certificate IV? Does Taiwan recognize these different levels? Do employers care? Certificate IV is twice as long as Certificate III yet only 25% more expensive. Quite strange. I wonder if I should go for the longer course as better value?

I found an FAQ here:
http://www.eslteachersboard.com/cgi-bin/articles/index.pl?read=1838

but it doesn't specify the type of TEFL certificate required.

Any suggestions?
Thanks. Paul.