add a 1 1/2" brown boarder and then a 2-3" cream or off white boarder (which ever would look best) then the polka dot boarder. you need to make sure that the all in balance with the sizes. so if you have 9" worth of boarder space a 1 1/2" inner boarder a 2 1/2" middle and a 5" outer boarder will all look good and in balance. but it is up to you. what I like to do is take a couple of pics and make a slide show on the computer of my different options and let it play for awhile and see what hits me as the best way to go. but that is just me.