I didn't know Jeep made Grand Ams.
However, its easy to find out if ite the alternator. Can you boost it to get it running?
If it can be made to run, check the battery voltage. It should be 13.7 to 14.5 volts when running and 12 volts when it isn't.
If the voltage when running is less than that, its likely the alternator.
Check your battery cables and connections, too. If one is bad, it can mimic a bad starter, alt or battery.