I know it's probably not what you're looking to hear but your scores are a little too low to qualify for a loan now. A co-signer will not help you either since lenders will use the applicant with the lowest score to go by. You should be working on improving your credit scores, if your determined you may be able to get your scores in the high 500's in a few months. I know several lenders that can work with scores in the 580+ range. Here is a link to our DIY credit repair guide to get you started, also has several dispute letter templates you can use. Good luck.