As mentioned below, your DTI ratio is one of the most important factors in determining a pre-approval. One thing you can consider would be paying down some of your existing debt that appears on your credit report. Removing this debt gives you a little more flexibility to increase your buying power. However, you then have to factor in items like "will you have enough funds to cover your down payment & closing costs." You should speak to your loan officer and see if there are any revolving accounts, auto loans or other installment loans that you could pay down to help increase your buying power.
One more thing to consider is to ask your loan officer what interest rate he qualified you at on an FHA loan. Right now, rates have come down and conforming FHA rates are around 4.50%. If he qualified you much higher, bringing the rate down will lower your DTI.
If you have any questions, i'm more than happy to help.
FIrst Capital Mortgage
DIrect: (310) 434-1718