I think a bit of selective brightening might help the image, by evening out the background somewhat. ultimately, you're striving for a calendar here, so the focus can't all be about the photo. having January, February, and April much darker than the other months is a little jarring. the background may also need to be more heavily blurred if you're going to layer transparencies - the bokeh is great as far as a photo goes, but again, the focus here is on creating a viable calendar.
a bunch of people have already mentioned the "2013", I'm just going to say I agree with them. lastly, the red numbers for the weekend dates can be very hard to read against the green background. it's not a highly legible combination which is why it's something that's typically avoided except at christmas-time - and even then, it's far more popular to use red/white or green/white combinations as they read much better.