see hiroshima, miyajima in 24 hours

We are taking Shinkansen Tour to Kyoto and Hiroshima.
We are reaching Hiroshima on 7th January, 2009 at around 3 pm.We are staying near Hiroshima Station and we will checkout and leave Hiroshima for Tokyo on 8th January at 4pm.
We want to see Hiroshima and visit Miyajima also.
I just don't know where to start. I would appreciate it if someone can help with an itinerary for Hiroshima and one for Miyajima.
Thanks in advance!!

I personally would directly head to Miyajima and spend the night and early morning there, before spending noon and afternoon in the peace park of Hiroshima.

More details:
http://www.japan-guide.com/e/e2160.html

Since many attractions (museums etc.) close at around 5pm, sometimes earlier you will not be able to see much of Hiroshima on the first day I guess. When you go straight to Miyajima, you might be able to see the big Torii - i's illuminated when it gets dark- and as far as I remember the last entrance to the main shrine was around 6 pm. so that would be possible for you. After that you can just enjoy a stroll around the island and eat some of the fresh-baked momiji manjuu, they are delicious.
If you already have a hotel in Hiroshima you can take the last ferry back and head towards the station. There are a lot of restaurants around the stations including some of the famous Okonomiyaki restaurants.
The second day start early and go to the Peace Memorial Park, all the main tourist spots are there. I managed finishing alomst everything in a day as well.
enjoy your trip!