Lower total ownership cost? (USA)

I drive a 1995 Ford Crown Victoria Police Interceptor which I'm very
happy with and which is in good shape. My wife drives a 1995 Mazda MPV
which isn't in great shape but isn't bad and runs well. They both
probably have around 120,000 miles on them, give or take.

I can't help but notice that we spend over fifty dollars a week on
gas. It would sure help our budget if we could reduce this. I'm
wondering if maybe we should get different cars, much as I love my
CVPI. I suspect I could buy a reasonable little car for as much as
I'd be willing to spend fixing up my CVPI if I needed to.

What I want is something that performs well. It need only carry me, so
maybe it could be more efficient through being much smaller.

What my wife wants is something that she can carry our two small kids,
me, and our groceries or luggage in.

We both want the cars to be comfortable (so we can drive long distances
without getting too tired), efficient, with a/c and cruise. Stick shift
is preferred, but automatic is okay. Neither of us are good mechanics,
so we pay a garage to do most of the maintenance.

So, can anyone recommend any comfortable but efficient cars that we
should be considering that would have lower total cost of ownership?
I'm wondering if my CVPI will last long enough that medium-term
maintenance costs will actually not be too bad (an excuse to keep it
(-, though it does still suck up the gas.

-- Mark