Stationwagon: Hook up your meter to the battery with it set to volts. A good battery, charged, at rest will read about 12.6 to 12.8. Start the car. Once the engine is running you want to see something higher than your resting battery voltage taken from before you started. ANYTHING above that voltage means the charging system is doing SOMETHING but you want to see 13.5-14.5 (ish). Rev the engine to see if that gets you there. If not you have a bad connection or a faulty component.
If you DO get a 13.5 or higher reading, then do the same test with the headlights on an maybe the heater fan (load the system), if you're still getting 13.5 plus thats good. If not, you have a weak charging system.
A good next step would be to yard the alternator and take to a part shop for testing--they can determine the current (amps) output under a load and get a real good idea of condition.