I suggest that you speak with a loan officer at 2 local banks. For the suggestion that one person recommended to check out a Land Contract or Rent To Own, you should consult with an attorney who handles residential real estate, to make sure the documents are prepared properly.
I can do an FHA mortgage with a credit score as low as 600 in California, so I am sure you should be able to find the same in Iowa. Start by visiting your local Wells Fargo branch and see what they have to offer.
One great way to get into a home now is to enter into a Land Contract or Rent To Own with someone. These are great as they allow you to start on the path to home ownership while you get your credit score up into the range to qualify for the mortgage. If you need help getting pointed in the right direction, let me know.