2001 Dodge Caravan issues starting!

I have a 2001 Dodge Caravan. For a while now it has been difficult to start. Sometimes it will act like it wants to turn over, and just makes that high pitched noise like when you start your car, and other times it doesn't do anything. When it finally starts to turn over, I have to put the gas to the floor to make it go and it will chug a little and finally start. I have been using a battery charger and it seems to help, but my battery has never been completely dead. All of the lights and door dings work ect, but its just not starting up. My clock however gets reset from time to time. Could this possibly be the Alternater not being strong enough or the starter, or just a bad battery connection?