Currently there are 5 native Telephoto Prime lenses for Olympus E-5 and 2 of these lenses are autofocus (AF) type.
E-5 also has a sensor based image stabilization system which means that all of these lenses will be stabilized when used on E-5.
Since Olympus E-5 has environmental sealings (Weather Sealing), you may like to couple your camera with one of these 2 Telephoto Prime lenses with Weather Sealings.