There are very few lenders that will lend with a credit score that low, even with that much cash down. I had a young lady this past year in a very similar situation. I am not sure if they are still doing it, but Wells Fargo and Quicken Loans were lending to low credit score borrowers with higher down payments. I have not heard if they have discontinued this or not, but it is worth the phone call. They will ask for an explanation of the funds and you will have to demonstrate that you are able to make payments on the balance. Lenders typically do not want to lend too small of an amount because it is not worth it to them and if the fees involved are too high in relation to the amount of the loan, they will not do it as it goes against federal guidelines. You really need to go to the source to get a real answer.
The question that comes immediately to my mind, as it will to lenders, is this: if your credit score is so low, how did you manage to get so much cash? The two don't usually go together. With a satisfactory explanation of this, I would think that someone would take a chance with you. With that much down, they have quite ample security and of course the payments will be correspondingly lower.
Visit with any licensed loan officer, after reviewing your overall financial information a determination can be made; if you don't yet qualify, he/she may offer great suggestions as to what needs to be done in order to be able to purchase in the near future. Be aware that a mortgage pre-approval letter is required in order to determine your price range and for any offers to be taken seriously.