Here is the link to a PKP timetable in English. Don't think it will give you fares though. As far as I can remember there is no direct service between the two cities and it was a 5 or 6 hour journey from memory.
there is no direct connection between the two the simplest and cheapest connection is to change trains in Kędzierzyn Koźle but the thing is there is only one train from Kędzierzyn-Koźle to Ostrava so it may turn quite impractical you can go for changing trains in Katowice (many more options)
will do some more research on that
oh and the duration of the jurney hmm maybe hmm quite long (the Kędzierzyn connection is the shortest one)