I need help..can someone please give me some advice??

I bought a 2004 Dodge Durango on August 29,
2018 straight off the lot. I never paid attention to
the fact that the sticker on the car said 05/18. I
waited for my tags so I could take it to inspection.
A little over a week my engine light came on. I took
it back to them and they said the codes were
stored old codes. (All they did was turn my engine
light off) the next day my engine light came back
on and I called them. They played dumb about it.
Eventually I started hearing a knocking noise. They
told me I had a warranty but it was a third party
warranty. They recommended a place and the man
told me I had a bad rim. I replaced that myself. He
turned my engine light off as well. I tried to pass
inspection and failed. I have a rejection sticker on
my truck still to this day. Also I signed a “as is
paper” not even realizing while the man was
talking to me ugh...also the codes on my truck are
issues in the transmission. One off hand I know is
P0700. I heard of the lemon law. Are they obligated
to give me another car or am I stuck with this
problem on my own? Can someone please give
me advice? I paid 3800 for the truck already out of
pocket.