Since we will be transferring our artwork to a canvas, you need to treat the text as if you were creating a printing block or stamp...it must be backwards on the computer screen, otherwise it will be backwards when transferred to your canvas. To do this, you need look closely at your composition and figure out any layers that have text on them.
Select one layer with text. Go to Tools-->Transform Tools-->Flip
Once you do this you will see a Double sided Arrow appear as your cursor. You need to click on your image, on the layer you are trying to "flip" and it should flip.
You may have to use your "move" tool to reposition your elements