A remix of http://www.thingiverse.com/thing:735726, by only taking the filament guide out of the stl and without the cleaner-hinge.
Update: completely remodeled in Inventor and smoothed out, file attached to fit your needs
Unscrew one of the top screw holding the Z-Axis Smooth Rods and put this little helper on.
Telfon Tube should firmly fit into the opening saying "T".
Then feed your filament through the bottom hole (hopefully saying "F") and through the Tubing right into your Extruder.
Have fun printing!