Start with Consumer Credit Counseling Service to get your credit issues under control and raise your score. I've posted the website below. They offer not only credit repair and management, but also they have education classes in home ownership and home buying.
I worked with one client who went through a credit repair place. He paid a monthly fee to them and they sent out letters contesting virtually every negative on his credit report. A lot of companies use that strategy. If a debtor doesn't respond in a timely manner, the credit bureau has to remove the negative whether it is a valid debt or not. The plan was then that he was to apply and be approved for a mortgage within that window of time before the companies put the negative back on the report.
Beware that it is one matter if the debt is a valid obligation and an entirely different matter if the obligation has been fulfilled and the negative has not been removed as required. In my client's case, the bombardment of letters ended up a nightmare for him. He had an issue with a car loan for a vehicle that had been demolished and the gap insurance was supposed to have paid the difference between what he owed and what the insurance company paid out. The issue had been dormant and the creditors had left him alone for three years. When the letters started going out, they started to make collection calls to him repeatedly. He ended up not buying a house and hounded by collectors.
In his situation, the issue did need to be resolved, but it also put undue stress on him at a time when he did not need that stress. If you work with a good company, they will educate you about what to expect and what is fantasy.
I certainly understand your situation. I've been there myself. I'm not a big fan of credit scores and I tend to think that too much weight is placed upon them, but they were developed for a valid reason. (My husband was actually instrumental in developing a system for the company he worked for.) They were meant to be a guide rather than an absolute.
It does not good for you to get into a home that you cannot afford to keep. Would you rather get into a home you love and lose it through foreclosure or wait a year and reorganize your finances so that you can get into a house that you know you can keep? It's probably won't be your dream home, but working with a good realtor, you can make a start on that dream.