. Guess I wasn't very clear.
you can render the particles within Maya's hardware render buffer (just search for that in the docs, they're clear once you know where to look) but when you render with that you get only the particles.
Here's a step-by-step type thing:
1) set up your scene
2) render everything but the particles with maya s/w or mental ray
3) render your particles using the hardware render buffer (make sure you render into a format that supports alpha, like TARGA
4) composite the particles onto the scene in a compositing program like shake or AE using the alpha layer
So you don't need another program to render the particles, but to composite them into the rest of your scene.