It's always a good idea to clean up your credit, because if you eventually want to purchase the home and obtain a FHA, VA or Conventional loan - this is criticial! There are some sellers who will do seller financing, but they'll typically want a good down payment to assume the risk.
There's lots of info out on the internet to help you .. the first step would be to get your credit report. I'd recommend that you work with a good mortgage broker who you trust. They can pull your credit for you and many will even work with you to make a plan on how to improve your credit and give you a realistic figure for what you might qualify for and how long it will take. Here's a few links on how to clean up credit:
Best of luck to you!