Beginner postprocessing software

I have the 7d and my graphic designer suggests I use RAW vs. jpeg. I would like the ability to update my photos on my website (as soon as it's loaded). The DiMage software leaves a little to be desired.

What's the learning curve if I take the dive with Photoshop CS? Is that overkill, and is there a better place to start? I don't mind putting out the $$$ if I can get the returns on investment.
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John Koessler