Addition Project Conundrum

I currently have 21x21 back porch with a shed roof that was enclosed with storm windows. I want to expand 2 feet East and West in order to tie into bay windows on each side. The problem is the porch pad is not level. Sloped as it was originally not closed.

Is there another solution besides busting and replacing the slab entirely? Framing the new perimeter and capping results in a cap that is too thin near the entry ways. The slope runs from about 1/2in by the current doors to 3 inches in the lowest corner away from the house.