Prices will vary depending on complexity of the site's structure and what your final requirements are.
I remember wishing to update my site and *not* wanting to spend a fortune, and finally settled upon a "template" site that I can change myself. It is fully independent of any other website (SmugMug etc) and meets my needs exactly. I did ask for some changes, which I was charged for, however they were reasonable expenses and the resulting site does everything I need it to.
I'm not sure how much your estimate started at, but I would expect that 70% more at this stage, without being able to update yourself, *not* having PayPal integrated and no slideshow working, means the designer has 1) grossly underestimated the time and features required, 2) has no idea of how to build a "Portfolio" site for a photographer 3) wants to make as much money as possible or 4) all of the above.
Yes, good website design does take time, however I would expect that somebody "who does this kind of stuff" would be able to estimate from my requirements much, much closer than suddenly being 70% over(!?) - photographer's estimates usually stipulate +/- 10% difference maximum.
Personally, I'd be pulling the plug now. 70% over estimate leads me to believe this person has no idea about what they are doing, and there's no guarantee that it isn't going to blow out by another 70%.