You haven't tried everything. You never should have gotten a credit card just so you didn't have a 0 credit score. WHoever told you that ......
I got my first credit card at age 50. I bought lots of houses. The lenders have learned an important lesson from the recent credit crisis. Having ZERO credit is excellent credit. It means that you have not screwed up your credit which is wonderful. THey gave me the loans based on my utility bills and my rent receipts. That is the definition of "good credit". You pay your bills on time.
You have a double whammy , tho. You are self-employed (a commissioned salesman is every mortgage company's nightmare - I know because i am one). And you don't really make very much money.
Here is what i want you to do. You need to find the cash to buy this house. 2 weeks or 2 years after you buy the house, banks will be lining up to give you a loan. THey always do. So how do you get $65,000 cash. You ask everyone you know. And you offer them 10% interest. A savings account at the local bank pays me 1%. I loaned out $63,000 to a young couple at 5.9% interest and i'm happy to be making more than the 1% from the bank. They pay me every month on time. Just like you will. If you can't find a family member or neighbor to do it, check your paper for a "hard money" lender. He will loan you $65,000 today but the rate is 18% interest. He knows you will be panicked to get his loan paid off. Don't rush too much. It sounds high but you will own a house and it's worth it. Then the same mortgage company that made you get a credit card will mysteriously be begging you to get a loan. I guarantee it. Get to work.