First thing I would do would be cover the board with fondant. Normally would do that a couple of days before and before placing cake. Since you already have the cake, I would place it right up to the cake and add a border like you did to the top tier. See how that looks. If you still feel it needs something perhaps you can cut some silhouettes of baby things like some of the items on here (http://www.shutterstock.com/s/%22baby+stuff%22/search.html). I would probably do it in the blue that you have already used.
