Just taken a good look on Wikimapia and you might be best emailing the hotel to ask --- we have not been to that side of the Red Sea so don't know how the hotels there are organised
On the Sharm side there is usually a Pharmacy close by one or two hotels where you can get medicines and Nappies as well as other items like GHD straightener etc (genuine ones too)

There is the Senzo Mall which is about a 15min taxi ride that has a Spinneys Supermarket (ASDA like) they will most probably have nappies, also there is a pharmacy at Fort Arabesque Hotel which I seem to of heard stock nappies, but I think Spinneys will be your best bet