At whole foods market they have celtic Sea Salt - if you can get that - put a small pinch of that in her water also (along with the little bit of lemon juice).
Is she getting any oils (or fats) of any kind? If she's not - try the small salad with olive oil - or maybe a little broth with a bit of olive oil in it.
The other suggestions are excellent advise, I don't know what you have access to, but as I said the noni juice (we get ours at Costco) or they may have it at a food store near you - has worked for some immediately and gently.
Castor oil packs are said to be some of the best medicine - are you near a whole foods market? they also have it there for $7.50 (must be cold pressed, organic for packs)
I will post the link in here in one moment for the full info.
Meanwhile, here are a couple of snippets, gathered from here at Curezone:
Castor Oil Orally: (***must be labeled for internal use****)
"Common Methods of Using Castor Oil
The most common way to use castor oil (and most objectionable, I might add) has been to take it orally. Generally, oral doses are used to correct constipation. The recommended dose is usually 1 tablespoon for adults and 1 teaspoon for children. You can usually expect a "purging" of the system in about four to six hours."
Externally:(**Must be labeled not for internal use**)
Castor Oil Packs
The most frequent use of castor oil is in castor oil packs. The packs are recommended for: cholecystitis (inflammation of the gall bladder), poor eliminations, epilepsy, various liver conditions such as cirrhosis and torpid liver, scleroderma, headaches, appendicitis, arthritis, incoordination between assminilations and eliminations, colitis, intestinal disorders such as stricture and colon impaction, incoordination between nervous systems, neuritis, and toxemia.
"Heat the Oil; dipping two, three to four layers of flannel in same, wring out and apply directly to the body. Well that dry heat be kept over same during the period of an hour or the like when the Packs are on the body. Bathe off the body afterwards, of course, with a weak soda solution, to cleanse the body from the acidity and from the natural secretions that arise from same." [Reading #1034-1]
"Be well to put oil paper or cloth over the Packs, for we should have great quantities of the Oil. Do not make them TOO hot, but so as to at least drive them into the body. It is well to put these on and then apply external heat; as the electric pad or salt bags or the like. DRY heat, though, rather than wet heat." [Reading #1312-3]
The suggested use of the castor oil pack varied from:
several hours at a time, until relief is obtained; to
continued use according to a cycle, such as three days of use alternated with four days off."
Useful for: 11. constipation, bowel impaction or adhesions
Buying Castor Oil
"Any oil that enters your body either orally or through the skin needs to be of the highest quality. Castor oil is no different. Check your local health food store for cold-pressed castor oil."
Take a moment, and let your mind fall upon what makes the most sense, what feels gentle and right, and choose your steps.
She needs electrolytes (water/salt/lemon) and she needs to soften the stool, I hope you get results asap - by the way, the castor oil can just be rubbed very gently over her belly and lower back.
Please know that I am only another parent, not an expert in any way. I can just feel your frustration and want to extend what I might consider in your situation.