I had the same troubles. What I did was picked a colour that was a little darker than I wanted and then after a couple of weeks of washing I ended up with the colour I was looking for and it didn't fade any further. As far as the red goes I had exactly the same problem when I first decided to go brunette. After trying a couple different colours and still seeing red in my hair I stressed to the stylist that I DID NOT want ANY red in my hair AT ALL.....and finally got a good colour now that I like.
I second the suggestion that you should try to wash your hair no more than twice/week. I've been told that by many stylists and I find that it helps keep my colour longer (and I have healthier hair because of it). Cooler water is also a good tip!!!