Jane, is there a reason you're not rendering to HD?
I checked their site and FilmFreeway recommends the following settings. I'd experiment with Handbrake (it's free and there are lots of "how to use" tutorials out there) to get the best results at such a low bitrate.
What format do you recommend for video uploads?
FilmFreeway accepts all major video formats in full quality HD up to 10 GB. We transcode videos for playback compatibility and performance and recommend that you use settings close to our output settings:
Maximum video bitrate: 2200 Kbps, H.264, mp4
Audio: 128 Kbps, AAC, 2 channel stereo
Aspect ratio preserved; maximum video height of 720 pixels