Have you installed the Cow on the host machine as well? That is necessary of course, otherwise it will ONLY be rendered on the other machine. That is not really faster then. BTW, the name of the host is "localhost" - if you want to add that Cow to the gang. Second maybe is, that Cow speed up only is relevant in big scenes, where administration time is not relevant compared to the total render time. With small scenes render times are not really shorter.

One day your ship comes in - but you're at the airport.