So the open strings are all in tune correctly, but the FRETS are all out of tune by about a half step? Without being able to see what you are talking about I can only make some guesses.

The first thing that I would worry about if that happened to my guitar would be that the neck is warped. With electrics, you can adjust the length of each individual string so that you can make it sharper or flatter if needed. On an acoustic, you are stuck with the string length you have, so the neck has to be good from the start. Because of the way guitars are, it is a little normal for some of the frets to be only SLIGHTLY off. But a half step is a little too much.

You might want to take it to the place you bought it from (or any guitar shop) and have them take a look at it.