complete renovation townhouse

Hi all, Sorry for my english (i'am french) We just buy a townhouse in Harlem to be renovated. (3400 sqf, 4 floors) All from basement to top (except roof) have to be updated, but as our fund is limited, we will just to repair ground and first floor to make a duplex and live inside until our finance increase. Now, we are looking for a contractor with hability to make a reasonable quotation. Just minimum : Plumbing, electricity, windows, doors, inside wall floor ceiling, one bathroom, minimum us kitchen... I don't know if a permit is mandatory? architect is needed? You can send an email dchialva@yahoo.fr or just reply... Thanks Didier