Astrocytes are the most common glial cells in the brain and are crucial in maintaining key functions of the brain. It has been shown experimentally that astrocytes communicate via calcium signals, and they regulate extracellular sodium and potassium concentrations. Mathematical models have been established to investigate either these calcium dynamics or these sodium-potassium dynamics of astrocytes, but no model has been published that investigates the interaction between these two systems. Here, we take the first steps toward such a model by allowing for the communication between calcium and sodium via the sodium-calcium exchanger. With this full model, we investigate the potential impact of sodium-calcium exchanger over-expression, and also describe one mechanism by which astrocyte calcium signaling may impact neuronal activity.