Buzz Lightyear!

Hi Everyone, please be nice to me I am completely new to this!!

I am planning to use a talking Buzz Lightyear toy in a little project where I want him to say my words - a .mp3 file. I m trying to find out if I'm able to use Arduino to do this?
I have found this:

http://www.instructables.com/id/Programming-Buzz-Lightyear/

It takes me so far, but I'm trying to add my own sounds and I'm pretty clueless to be honest. Can you wonderful people help me?!

If you need any more information, please let me know.

Not sure the chip used in Buzz is reprogrammable.
Probably have better luck using Arduino to command a module like these to playback MP3 files: