Alright, this may or may not work, this was made like a year ago so if this fucks up- sorry 

1. Put DC_Artemis.wad in the Addons folder in your DRRR install folder.
  This contains the 2D sprites and audio- mod is functional from here when you enable it in game.
  If you want the model though, move along.

2. Put KARTEMIS.md3 and KARTEMIS.png in RingRacers>models>KAPL

3. Go back to the RingRacers folder and open models.dat as a text file.

4. Add the line [[ ARTEMIS KAPL/KARTEMIS.md3 3.0 0.0 ]] to the top of the list, and save the file.

And now it should work when you switch your rendering software in game.
Have fun!