Are you calling the cruise companies directly or dealing with an agent in Egypt? I'm not surprised you're having a tough time with a very specific itinerary like that because many of the cruises are booked by two or three groups at a time (not necessarily traveling together, but booked through the same packager). A single traveler is at a disadvantage, schedule and price-wise. Your best bet is to find an agent who's already booking a group for those specific dates and seeing if they'll squeeze you in. But since you're not part of a group, I'm not surprised you're finding the pricing that much more. A lot of the profit on such trips comes from booking side expeditions, rather than the cruise itself.

Anyway, bearing all that in mind, I've had good dealings with Galaxia Tours: http://www.galaxiatours.com/index_2_english.htm