First you would want to contact your landlord to see if they would even consider selling the house. From there you are going to need to speak with a loan officer to get pre-approved to see if you can be approved and for how much. If you are approved make sure that you are comfortable with the payment and don't just buy as much as the bank says you qualify for. Make sure it fits your situation and you are comfortable.
Best of luck to you.
REALTORÂ® | Mortgage Broker
Keller Williams Realty | 360 Lending Group