Move or stay?

So I have a 4 year old son and am expecting our 2nd baby. Our current home has 2 bedrooms upstairs, our room has a 6'×10' room attached to it we use as a kinda closet deal and we have a spare room downstairs. I'm having problems trying to figure out how to make our home work. I don't want any of my children being on a separate level of the house as us but I am just not sure what to do. We live in a small town so houses are sparce. Any advice???