FHA Pre-Approved: How To Increase Loan Amount?

[Ryan Barr]

Struggled with the title. 

Like the title says I was pre-approved for a $235k FHA loan without a property in mind. Theoretically, I find a duplex worth say $280k, with a tenant in one side paying rent. I go back to the bank, adding that monthly rent to my income and potentially get approved for that higher price? Also if I have a roommate agree to paying me monthly as well does that count towards my income?