almost certainly the best/sanest/most thoroughly research-driven resource on recovering from eating disorders is youreatopia
the blog posts are all great and highly informative, and you should read as much as you can, but the short answer is 3000 cals/day m i n i m u m (!)
this is the amount that, taken in consistently, should be enough to get your metabolism back on track and your hunger signals firing again–don’t be surprised if it’s difficult to eat that much for awhile, and then suddenly you’re incredibly freaking hungry and are eating two or three times that no prob; totally normal and necessary
disclaimer that this approach doesn’t work for everyone (gwyneth is all about erring on the side of caution as well as tough love) but it’s an excellent place to start no matter what, imo
best of luck to you; you’re on the right track and your perspective and attitude seem great–keep it up/screw that nutritionist