Just from what you say, I'm guessing that the problem is not so much color, but color value. CraftyBear posted a link to an article about using color value in your quilts today. See Color Wheel Basics
http://quilting.about.com/od/colorfa...lor_quilts.htm
and Using Color Value in your Quilts
http://quilting.about.com/od/colorfa...olor_value.htm
Color value makes all the difference.