3d rendering question - quality problem.

I'm pretty new to rendering, so I'm sure that this is probably an easy question...

My problem is that the quality of my rendered images are awful, and they do not look as good as they should. The attached pictures should show you what I'm talking about. One picture is a screenshot of what I want to render, and the other picture is the final rendering. As you can tell, the rendered image looks significantly different.

What settings do I need to tweak so that the rendered image looks exactly the way the model in autocad looks? I've tried to increase the render quailty, but still looks the same.

Note: the model drawings were done as examples.

Try this: http://www.cadtutor.net/forum/showthread.php?t=35688