I need a little help
 

So let me start off by saying I am new to this forum. I will probably ask questions that have already been answered. I did a search but didn't find them that easily. I have an older road bike with components that match. I have been toying with keeping the frame for a while and upgrading the components. I just don't know the compatibility of what I have vs. what I want. I don't know if I have to do it all at once or I can do it piece by piece. I am running Campy Centaur 10 speed circa 2004. I would like to upgrade to Chorus, Record or Super Record. I would like to literally do it a derailleur at a time. but don't know if that is possible. The Rear Derailleur is in need most. Do I have to change the cassette and shifters at the same time or can I get by with my Centaur's for a while?

Any help anyone feels like offering is appreciated.

Mike