First thing is to talk to a mortgage professional and have them look at your credit. If your credit is on the edge of where it needs to be to qualify, the best advice I can give you is to take 3 or 6 months to work on cleaning up your credit. Sometimes cleaning up your credit can be a simple process and can go quickly if you work with a lender or credit professional to do so. I am not a lender, I am a Realtor, but I could certainly give you some recommendations for folks I use in the Olney area. Once you have your credit up to where it needs, we can figure out what sort of monthly payment you are interested in making. That number, along with area taxes and home owners insurance, will let us know what sort of purchase price to be looking for. Once we know that, I can tell you how much money you might need for a down payment. For instance, $100,000 house would need at least $3,500 if you went with an FHA program. If you need any more advice, please feel free to ask.
Have a great Monday!