First of all, let your landlord pay to upkeep the house. It is his house and his responsibility to maintain it. Keep it clean and maintain it in the current condition. He probably wants to keep the house now so look for another house to purchase. Begin a plan to pay-off accounts and lower your total overall debt. Lenders look at your debt ratio when lending money and your ability to re-pay when granting loans. For example, if you have $10,000 in total credit but, have used $9,000 of that credit you are close to 'maxed out' and therefore, probably not a good candidate for receiving a loan. On the other hand, if you have $10,000 in total credit but, have used $1,000 of that credit or about 10% of your available credit you have flexibility in your finances and probably a good candidate for a loan.
When you open up a credit account, your credit score will increase by around 15 points or thereabouts. Find a credit card company designed for customers with lower scores that enable you to increase your credit scores. See the link below for secured cards.
If you have any small past due or late accounts, pay them off first. It will take time for your credit score to improve after starting a program to increase your score.
Lenders also look at your debt to income ratio, "What you earn versus what you owe will determine how much you are able to borrow. This is known as the debt-to-income ratio, and conservative 36% debt-to-income ratio is used for prequalification. However, excellent credit patterns, job stability and substantial assets may allow for a higher debt-to-income ratio."
Pay down debt, pay off accounts and save as much as possible.
If you have a down payment on a house that is less than 20% you will need to purchase property mortgage insurance which adds to your mortgage payment.
There is no simple answer solution to your situation without knowing all the details. Be frugal in your spending, save as much as possible every month, pay off debts and look to reduce any monthly expenses such as: rent, auto expenses, utility charges and non-necessary incidentals. Good luck.