I don't know where you live nor the prices of homes in your area. If the prices are right, you have a fighting chance of getting you a home. I see that you are currently paying $900.00 per month for rent.
You have a challenge or two to overcome, but they can. You interest rate will be a little higher, your choice of mortgages will be an adjustable rate mortgage fixed for either 2 or 3 years. Select the one that you would feel comfortable with. The rate and payment will be the same for 2 or 3 years, that will be determined by which you select.
Once the 2 or 3 year period is up you should refinance your home to a new mortgage. Now that depends on if you have paid your mortgage on time. If you have you will not have any problems what so ever. If you have not you will be in the same situation as you are now. If all else fails make sure that you pay your mortgage on time. Please do that. By paying your mortgage on time it will increase your score and the 3 years will give you time to get back on track with paying your other debts.
My take on real estate is that you should buy real estate and wait, not wait to buy real estate. That same place you will buy today in about 3-4 years will be a few thousand dollars more. That is equity that you would have built up over the same period. Remember the interest you pay on the mortgage no matter the interest rate is tax deductable. check with your tax advisor for any and all tax questions.
You need to select a "Mortgage Broker" that deals in sub-prime lending with your score. Stop going from broker to broker, if you have submitted your application to a few already select the one that you think will do the best job for you, the most important thing is make sure he does sub-prime loans. If he does not you are wasting your time as well as his, so find one that does. Call the ones you have submitted a loan request to and see which of them that specialize in sub-prime lending.
He will request personal information from you that you should supply as soon as possible. He will secure you a loan pre-approval.
Once you have your pre-approval you may go shopping for a home, either with a realtor you know or with one the mortgage broker can provide for you.
Once you have found a home for yourself, the real estate agent will get a contract drawn up between you and the sellere for both of you to sign. He will also provide a copy to your mortgage broker.
Your mortgage broker will at that time order an appraiser to verify the value of the property.
Your mortgage broker will probably want additional information, but that is normal, so don't blow a gasket.
He will also open escrow closing agent, secure a title report for the property, order loan docs for you to sign.
I hope this has been of some use to you, good luck.