We live in Iowa and our landlords sold the house, now they tell us we have until feb 2nd to move out because the new owners want to move in-our lease is good for a year and we have only lived there for 4 months?

So you ask them how much are they going to pay you to buy your lease out? Your lease is valid, and they can not evict you. The new buyers will have to honor your lease when they buy. So if the seller wants you to move out, his only choice is to offer you enough money to make it worth to you to move.