04 pontaic grand prix wont start has 219k miles on her

Ok I wanna start by saying I was driving the car to
town and car was fine in about a 3 mile stretch it
went from normal heat level but cold air blowing
out heater to almost in the red line area I pulled
over got a ride and 30 mins later came back it
didn't need much water even thou there was a
puddle under the car a small one we started the
car Reved it up and the heat was normal even was
blowing out hot air from heater started driving
home and on the big bridge in my city she started
having a issue I tried to speed up after slowing
down for a curve and she acted like she didn't want
to then she did so I went about 62mph on bridge
and about 5 miles after getting off bridge (15 miles
from the first problem) I had to slow down to 50
and she didn't like that she started going slower
and slower and I had my foot on gas trying to go
the rpms would go down then jump back up over
and over eventually I had to pull over and park and
that's when I noticed the car had no steering I think
it shut off but then I don't cause when I tried
shifting down out of over drive or to neutral and hit
gas she shifted but didn't respond to the gas I
ended up parking car and waited like 10 mins and
tried to start it she sounded like she was going to
then she didn't it was kinda shaking so to say when
I was trying to start it help me i don't know what
happens I do know my check engine light was
already on for a o2 sensor and i just changed the
fuel filter pump assembly about 2 or more months
ago I don't know if putting different antifreeze in it
then what suppose to be in it was mostly water but
don't know if that would cause the issues but it
wasn't overheating when she broke down the
second time help this is my only car and i have a
kid so we depend on this vehicle for everything
thank you and if u also could give me price points
on what it would cost for parts to fix it I'm sure as
long it's not to big of a problem I could do this
myself. Thank you kn-motto