Hello!

So first i was having a Cylinder misfire so i changed my spark plugs, spark plug wires and my ignition coil. Non of those fixed my misfire. Then one day my battery died while i was driving so after that happened I replaced my battery. I was still getting the misfire so today I had a mechanic looking at it and they said it was my fuel injector in cylinder 3 and they quoted me at $950 to change it so i said hell no to that and i just changed it myself and I do not have a misfire anymore I fixed it for $80! but as i was driving around my rmp gauge, mph gauge and radio and windows rolled up very slow so all those stopped working and the gauges went to zero as I was driving.

Even though i replaced my battery a week ago my car still died. So it must be the alternator right?

Thank you very much ahead of time!

Depends. May be your battery is bad. But while driving everything happened, so I suspect the alternator.
Check the voltage while engine is running. It should be above 13.0 volts. I get 14.2 with AC/Headlights/wipers on.
If the problem is with your alternator, you can pull it out and inspect the brushes. These are the first thing that goes bad (wear out). You can buy replacement brushes on ebay or may be from the dealer.

Brushes look like follows: Most toyota brushes are identical and interchangeable
Alternator Brush Holder with Brushes Denso 021620-2010, -2180, -2200, -2201, -2630 - 1993 GEO STORM 1.6L NEW ALTERNATOR - 13569

for $950 + $300, you can get a low mile JDM engine installed!

You can test your alternator easily. With the car running, unhook the positive on your battery. the alternator must be able to run the vehicle and all of the equipment flawlessly. The idle May drop slightly, but it should maintain the vehicles stock equipment. If it doesn't and the car dies,not here's your problem.

awesome i will go check this out right now and I will get back to you!

now I am leaking where the fuel injectors are, injector 3 and 5.. how should i fix this now ?

I replaced my my injector 3 and then my injector 5 started leaking. and now i decided to switch 3 and 5 to see if it fixed the problem and now both of those are leaking!