Midi keyboard (Hello, I really need help)

by gabriel
(beijing, China)

My name is Gabriel, I'm Argentinean but living in China since a 2003, I have start playing bongos and harmonica for a while, and now I'm trying to learn how to play the keyboard.

Actually find a job as musician in China is very easy and you may see some good money, so I noticed that many band here are mostly "playing" not much and let the keyboard do all the job, I'm referring to the midi player, they just play a midi song on the keys and play the instruments over that midi that comes out of the keyboard.
So I want to buy a keyboard that will do that job for me a good "midi player" with realistic sound and as cheap as possible with a sd slot card or good capacity to store many songs.
I just bought the casio LK78CD it's a casio model that's its sale only in China so there isn't much information about it, what do you think I should do?
Is it any of the yamaha good for what I want?
thanks a lot in advance.
Sincerely:

Gabriel