You can also get a secured line of credit... Way better for your credit, it's like a credit card, but it's backed with a secured amount of money put up by you, like $500+... This greatly helps you build your credit.
You can try a different lender, I have heard of a few lenders who will lend to clients with a credit score as low as 580 now. Every lender is a little bit different. But your credit score isn't all that is necessary to qualify for a mortgage. There is more to it than that.
Email me if you would like a couple of contacts that may be able to help you, my contact information is below.