Rotobrush isn’t exactly intuitive, you might want to to watch a few tutorials on Rotobrush, because from your brief description it sounds like it’s working the way intended. It only does about 10 frames and then you have to extend the frames it will do out or set start frame selection. It takes work, but compared to actually cutting the person out frame-by-frame, it’s really quicker.
Here are a couple of tutorials that might help you understand rotobrush better.
AfterEffects CS5: RotoBrush
How to use the Roto Brush tool | lynda.com tutorial
I messed around with your image and it’s not hopeless, but that image will take a lot of work. Did they use a filter in camera to achieve that color? Was that backdrop there with the idea of keying it in post? If that’s the footage you received they didn’t go out of there way to make it easy for you. The feathers are going to be particularly tricky. This might be a case where you will need to rotobrush, mask and possibly key to get an 100% perfect pull.
Here’s my results, quickly messing around with the rotobrush. 
Johnny Cuevas, Editor
Thinkck.com
“I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work.”
—THOMAS EDISON on inventing the light bulb.