It sounds like the cable that goes from the shift lever to the transmission
has slipped and gotten out of adjustment - there is an adjustment procedure,
should not take the shop too long to adjust if that is all that is wrong.

There is a "parking pawl" in the transmission that holds the tranny in park
when you move the shift lever to P - sometimes they have problems, but since
you noticed that your shift lever is out of adjustment I'm guessing that is
all that is really wrong

I had the same problem with my 97 f250 4wd diesel. I was all set to
try and adjust the cable at the trans but couldn't get the clip off. I
then went to my all data online manual and saw a recall notice about
the shift cable. Well the fix they had wasn't what I needed, but it
caused me to look under the dash and I found that the bracket that
attaches to the shift lever on the steering column and has the cable
attached to it was as loose as a goose. The screws had started to come
out and after I tightened everthing up it is working as good as new.

dave