Tips: If you do not have a credit card, get one.
You can get a secured card, if need be.
Use it as you would cash, making the purchase with the card
and pay it as soon as you are able.
Going to near the max and then paying it down quickly helps also.
These can boost your credit scores a lot faster than other methods.
Best of luck.
Having a fixed income will not keep you from getting a home loan. Your first step should be to talk to a loan officer to determine what you can qualify for. Do you know what your credit is like? Check out http://www.UrbanPhoenixRealty.com for more info!