2005 VW Jetta 2.5L/ water pump & misc issues

My car was or seemed to be, running
great. Really fun to drive, smooth, fast,
perky. Until one day it seemed to lose
power ( of course I was on the
freeway) & I saw it was overheating. I
tried to pull over as soon as I could, but
it was several miles, & the engine died.
No smoke, just dead. The garage I was
towed to said it's the water pump. After
that I was reminded that I was
supposed to put water in the car
periodically, but car stuff just doesn't
compute well with me. Is it expensive
and/or a huge job to fix, is it worth it &
if so, are there any other things that
ought to be replaced during this
procedure? A video said some screwy
looking thinga-ma-jig should be
replaced & maybe some gaskget.. (
don't know how to spell that word,
sorry). Plus the battery is deader than a
corpse.. but my car has been sitting
waiting for my son in law to fix but now
he says he will have to pull out the
entire engine and I don't think that
sounds right. (Plus he's a meathead).  I
think the battery which was relatively
new-ish is dead cuz a door was left
ajar, plus sitting for eons waiting for
meathead, causes that, yes? Maybe?
Is my car fixable or hopeless? I need it
until I can replace it and it's killing me
to pay Uber.. I need some serious help,
good advice, & a small miracle. Thank
you.