No matter if im driveing or parked i can not use my Ac or heat it shuts my car off if i turn it on

Got tb car from my aunt who stopped driving it for like a year due to multiple problems.
I replaced the battery and got it running enough to get it home. Ran really rough and smelled like old gas 2 bottles of fuel conditioner and its a lil better. Now when I start it up after it sits it acts like its gonna die when I press the gas. When I'm on my way to work if I have to stop at a light it either stalls completely when gas is pressed or just hesitates and goes. Have had a few back fires and 2 times it died while doing about 55. Cel is on during the drive to work it starts blinking sometimes it stops blinking. I know when its blinking it really stalls and strains to keep going. Misfire code from auto zone. I don't know if I should start replacing things with out reason and my wallet tells me I def can't do that lol. Any idea what can be causing the misfire?

What is the spss light? Is it safe to drive with it on?

At first a fuse for the interior lights and headlights had blown so i located it and replaced it. then as i was driving my speedometer did not work. my check engine light came on then the airbag light and then my power steering failed and my car died.

At first i thought it was the alternator so i replaced it but as i drove home the same things happened so im lead to believe its the voltage regulator.

OBD II wont come up with ok changed battery mow not ready

Also changed the valve cover gasket at the same time.

Just need to know how long it takes to fix as well

It fumbles when I stop and smoke from exhaust