Need help, battery doesn't charge

Hi!

I accidentally got the terminals on my battery  the
wrong way, ( like the positive cable connected to
the battery's negative and the positive on the
negative) not noticing it, my dad started the
ignition and it did not start and suddenly
something sparked and smoke came out under the
engine. After that, we reconnected the cable to its
corresponding terminals and then started the
engine and noticed that all the LED displays such
as engine check, seatbelt sign, oil, and the
backlight of the dashboard doesn't work as well as
the radion. We tried to bring our car to o'riley and
autozone, both tests says there is a problem in the
voltage regulator. We bought new alternator and
battery, but still the problem is there and the
battery still does not charge. Would like to know
what would be the problem and solution.

Thanks and hoping someone can answer this
inquiry.