Well... You have a 100% image based site so ya, its going to be slower then a site that is built on web using good old web text and css. Why not try minimizing your images. I see a number of images that have a lot of white contained in them, why not trim that out as it is not needed. Also, seems that you have a lot of slices that aren't needed. Try minimizing the number of slices.. example, bottom row could be one long slice. Maybe also try working with different compressions schemes or applying more to the current images, front top slice is 160kb which is a bit much in my opinion. You might also want to consider adding in or replacing some of your text with web text so that the search engines can find your work.
All that said, I think if you were to keep this set up, using imageready, then I would suggest working on your compression settings, lower the file sizes.
Good luck
Off subject, I am a bit confused as to why put work up if it is all to be password protected.