I have one in contract right now, and the buyer's is getting a 20% downpayment assistance.
Please visit the S.F. MOH link below for more information.
Contact me if you have questions.
Barbagelata Real Estate
I've worked with a lot of great mortgage brokers, happy to put you in touch with one of them.
Talk with a mortgage professional and let them run the numbers for you, but don't let them run your credit, at least not yet.
Once you have saved enought money for a down payment, then have them run your credit and get pre-approved for a loan.