Nutritious soups/stews a good start, my MIL (Jamaican) made some fantastic ones with chicken feet or fish heads, potatoes, carrots, turnip, herbs, stock and anything else you fancy throwing in.
In place of fish heads or chicken feet (which carry a lot of nutrients) you could use chicken wings or oily fish including skin minus the head if you are a bit squeamish. You can also make stews with something like lamb neck or oxtail which are also good.
Daily multivitamin, lots of fruit, smoothies, fruit lollies, fresh juices, vegetables.
Lots of sleep.
Get some toys/games that you can play together that don't require lots of energy like puzzles, play dough, painting.
New books you can read together.
Baking another good one as cakes/biscuits will get her appetite up!
My DD (2.3) loves the Tweenies Song Time and Backyardigans DVD's to dance around to or you could put on a childrens song CD (ELC do some good ones) and have a bop together.