Hmm ... actually, with Maya you´re pretty much on the way and you can
finish an animation of production quality with Maya alone. However, you could try getting a renderer and with Mental Ray being a freebie to Maya 4.5 users it´ll be quite a lot easier.
You could try using yourself a bunch of programs but, not one of them has a magic button that says "great animation", that´ll have to be yours and as such if you use Maya at a certainly more advanced level, yoú won´t pretty much need anything else. (perhaps a composer though)
My workflow would be this one:
-Create a storyboard, plan out everything first.
-Create the models in Maya
-Texture (or shade them)
-Rig the models
-Prepare the scene (Lights and such)
-Animate the models
-Render (perhaps MRay?)
This workflow itself is guaranteed
to keep you busy for months if you intend on doing more than one minute.