Alternator for 2001 dodge grand caravan?

My dodge grand caravan wont start, unless it's jumped off, and then dies very quickly. I got stuck at a gas station and luckily got it jumped off to get back home, but the whole way home the odometer and rpm gauge were jumping around and the lights were flickering. when i got it home, my husband turned the headlights on and it immediately died. I have very limited auto repair knowledge, but Im pretty sure this is the alternator. Can anyone confirm that? Or could it be something else? If it is the alternator, does anyone have any idea how much one would cost, and if we could put one on ourselves? any info is greatly appreciated!!