Parts too thick and holes not well defined

I'm printing the prusa i3 bearing holder for the y axis, the part is supposed to be x:10mm y:25mm and z: 9mm but this part is comming out just a bit too thick like around .6mm extra. Also the holes are supposed to be a hexagon but are coming out not well defined. Any suggestions, ive been playing around in the advanced settings in slic3r extrusion width permiter settings to no avail. Anyone have any ideas?

Ive attached a pic of the "hexagon" anyone know how to clean the shape up?

Have a look here, check your alignment, wall thickness and so on with simple test cubes and objects with single walls (printing with "spiral vase").
Once you have done the initial calibration of filament, extrusion width and nozzle diameter the print should be in the same dimensions as your STL file.
For small holes make sure have the temperature for the filament right, too high and the walls can sag, especially when the overall size of the object is small.
You can help by installing a cooling fan pointed at the printed area around the nozzle.

Just a guess since can't see the photo well, if you are extruding too much it will make a hexagon hole look more rough round. Make sure you measure your filament and put that value into the slicer. If it already is, try lowering the "Extrusion Multiplier" try a setting of 0.85 to get started.

If this does not work and you followed the info in the other post, then post a good photo showing the product, many times the way the surface of the material looks will give clues.