Trish, first of all
!!!
Are you talking about brown rice, potatos and whole wheat pasta? If that's the case, yes, you can have one of them, once a day. If you have a potato for lunch and brown rice for dinner, you need to use your 35 WPA on one of them.
But grains such as bulgar, barley, oats, wheatberries, quinoa and wild rice as well as others, can be eaten as many times as you want in a day. There is no limit to them.