Car hire Tulear

Hi
I'm hoping to get to Beza-Mahafaly from Tulear and return by Taxi-Brousse etc. However, due to time constraints I may need to have an alternate plan i.e. hiring a car. Can anyone recommend a company in Tulear that would hire 4x4 and driver to take me there and let me stay for 1 or 2 nights. I don't seem to be able to get to the website of Compagnie du Sud that is mentioned in Bradt. What are approximate costs of hire?

Thanks