I am hypoglycemic too. But I can't eat brown rice because it would give me major IBS pain. I have to stick to white rice. There are many different types of white rice (not just Uncle Ben's) so maybe one of the alternative types might work okay for you. I am trying out organic basmati at the moment and doing well on it!
As for the potatoes, could it be you are eating conventional potatoes? My tummy hurts from those too. But I've been fine since I switched to organic potatoes. Have you tried organic?
Unfortunately the IBS diet is not exactly ideal for blood sugar problems. However, the IBS diet has to come first because otherwise you may be in constant pain.