You definitely need a new battery.
Examining finances, frequency of camping, degree of working the battery (are you a light, medium or heavy user?) and method of recharging, should point you in a direction as to deciding a flooded battery or a sealed AGM battery would be the most intelligent choice.
Then you need to verify the battery is getting a correct charge from the vehicle alternator.
After that you need to verify the battery is getting a correct charge from the on board converter.
One step at a time and it will not be daunting.
Do you have a nearby HARBOR FREIGHT STORE? A twenty dollar handheld multimeter is going to be worth it's weight it gold. No worries. You will be using it at one single selected setting - DC voltage. But get the meter now. Later on you will have it and you will be guided here, step-by step how to use it. It is ultra easy. Even a carpenter can use a meter correctly :)
