Does anyone Talk Box or know who to make this sound more like a Snyth?

The closest thing I know of would be a vocoder but I know of no vocoder that works with Garageband.

This guy has an interesting video on making a "Talk Box".
http://www.youtube.com/watch?v=9EIQxwotn3k

Closest thing would be to

Open a real instrument track with a mic hooked to it...

Open the edit window and turn "Enhance tuning" to the max & select limit to key box below it.

Go to the project box and select what key you want.

You can get pretty close to a vocoder. Hope that helped.