CAD Designer, Sourcing

Can anyone suggest a good company to use for CAD designs. Where I can purchase wax resins o designs to cast.

I currently have the Durabull Tabletop Casting Unit, Programmable Rio Kiln, Rio Electric Melt Furnace and Polisher set up.

Until I improve on hand carving, is there a reputable source one can trust for ring designs, charms etc?