that's what i was thinking, except i would probably do 2 of the 2400's just in case you know...just fyi, it wont help your alternator.
it wont really do anything but put more reserve energy to play when the car is off. and if you do that its gotta charge all 3 of them back up.
imo - a 2400 and a new alt for your next car is the way to go.
i would buy one of them local. i would then wait till i got the new car, and i would get a new alt.
thats just me.