Dust collection is quite a problem using regular air cooled routers due to the air that exits around the collet. The air circulated fine dust around my basement so this was my solution....
Step 2: Computer-Aided Design and CAM
The top piece simply clamps to the router and the vac hose.
The bottom piece is designed to allow the collet through but deflect any exiting air from the router out the sides.
Creo doesn't export nice round circles by default but I didn't bother changing any settings. The .stl export feature in SketchUp has given me more round circles. I stuck with Creo because it is easier for me to define features.
I have used MeshCAM 5 pretty much since I started out since it is very simple to use. Their site, GRZ Software, states MeshCAM is for non-machinists and they really do mean it.