Dear Keyboard Players (and related experts) --

How can I play synth sounds with my digital piano?

Here are the details...

-- I have a digital piano, the Casio PX-130...

Amazon.com: Casio Privia PX-130 88-Key Digital Stage Piano: Musical Instruments

-- The piano has one MIDI connector and two 1/8" stereo mini output connectors.

-- From my basic research, it appears that I can go more or less one of two ways...

...(a) get a synth sound module and run the stereo-output or MIDI through that and then it will output synth sounds...

...OR...

...(b) run the MIDI output from the piano to a computer and run it through a software-based sound module and then output sounds from there.

My requirements are the I need to get a small but decent range of spacey synth sounds, along the lines of Jordan Rudess and Jan Hammer sounds (though not that many), plus I need a few organ sounds along the lines of the B3, plus I need some nice acoustic Grand Piano sounds.

Budget is a major factor and I need to keep the numbers low on this-- Under200=Good, Under100=Better, Free=Best.

So, my questions are...

I would prefer to use a computer and a software-based sound module so is that advisable?

To use a computer for this, do I just plug in the MIDI to the piano and the USB to the computer and then the output come from my computers headphones jack?

What software do I need?

Since I already have Band In A Box which has tons of sound patches, can I use those?

Is there any freeware available?

Also, if I went the external synth module route, what is a good starting point for an entry level sound module?

What do you recommend in general?

Thanks.

-- Mark Kamoski