Where do i find pro bono grant writers that will accept payment after the grant has been successful?

im a felon with a very creative mind i have invented something that addresses and solves a major pet problem however my consultant has passed away and she was my only chance at making this product successful. Now im left holding the ball and need $. im left with very little insight and i really want to get this going asap!!! all that stands between me(reasearch done prototype done casting and molding company found) and my success is a very elusive grant!! the product is also green,american made,and has life time guarantee. its even half way made!! somebody plz help me help a grant writer get paid!!!