Adding new sounds to CP33

by Butch Hoover
(High Point, NC, USA)

The only keyboards I own are a Yamaha G-2 and a 1980 Fender Rhodes FR 7710.
So, I know nothing of midi's, sequencers, etc. What would I need to buy in order to add more (or better) voices to a CP33. Let's say I wanted to add a really good trumpet or flute. Or maybe I'd like a better Hammond B-3 "voice" .
Remember, I am completely new to this, but we're thinking about getting a band together to play some old 80's rock and blues. The CP33 does it for me on the acoustic piano sound, and it light enough for me to move around by myself. I sure don't need a 70 lb CP300. My back doesn't want to hear about it, if you know what i mean.
Thanks.

Signed,
Child of the 60's