Improve your credit first. The wise thing to do is NOT to get a house you can't afford. Once your credit is better and you save up a down payment your interest rate will be better.
Keep track of every cent you spend for at least a month and see where you can cut down and put more money on your debt. So much money is wasted on useless stuff and people don't realize it. Bottom line...get responsible and give yourself a few years to get out of debt. You will reap the benefits for the rest of your life.
You can get help by checking out the Finance the Dream site which offers help people own a home despite their bad credit history. This is only if one is serious about owning a home since they have a program that may work for you which can also restore your credit history. Check out http://www.ehow.com/buy-a-house-with-bad-credit/ for more details on how to own a home with a bad credit history.