Is This A Big Problem?

I just bought a 2007 PT Cruiser from a person who said that it only needed a
radiator. My uncle let it sit running for for 45 minutes to see if there were any
leaks and saw none. He figured it was just a radiator cap needed and
antifreeze. I got the car bake from him and noticed that when I shift from park
to reverse I have to pull twice to neutral. And from reverse to drive I have to
go to 3. On the dash, it reads the gear ahead of what you're trying to be in.
So, on the dash it's drive but on the stick it's 3 in order to be in drive. The
main issue is when I need to park. When I stop and put it in park, the car will
park but roll back just a little when I take my foot off the break. At that point
the dash will say it's in reverse. I have to turn off the car, release the break,
turn the car back on without cranking (it won't crank anyway because it is
considered in reverse) then pull the stick back once and then back into park
in order for the dash to read it as in park. Otherwise, if I don't do that then it
will not crank up the next time because the dash would say it's in reverse. Is
this a big or bad problem?