CD Changer Installation

Hello to all,
I am in a bind. I just purchased a 99 C280 and it has the AM/FM cassette radio but no CD changer. It is the stock radio with the 1-9 keypad to the right. I had wanted to install a direct wired unit but don't have the bucks at this time. I still have my old Pioneer RF cd changer I took out of the car I sold and was thinking of installing it until I could save up enough money for the unit I want. Does anybody know what type of antenna adaptor and how to wire the cd changer. From my previous installation I know I need an always on connection and one that works on the ignition. Thanks in advance for any help.

Billy