Magnesium is also a vital component in the bone building process, but it is often neglected.
You should be able to get adequate Vitamin D if you have normal cholesterol levels (180-240 mg/dl) and get out in the sun frequently (vitamin D is manufactured in the skin from sunlight and cholesterol). Cod liver oil is an excellent source of Vitamin D and the essential fatty acid Omege 3 (EPA and DHA).
You mentioned gall bladder problems. What is your cholesterol level? The reason I ask is that people with gall bladder problems or lack of a gall bladder often have unacceptably low levels of cholesterol. Contrary to all of the medical and media hype, low cholesterol levels can have serious negative health consequences just like excessively high levels. Studies have shown that your overall risk of mortality is greater with an abnormally low cholesterol level than with an abnormally high cholesterol level.
Over 50% of bone structure is protein, so if you aren't eating adequate levels of the nine essential amino acids (protein) like that found in animal products, it will be difficult to build new bone.
Dark green leafy vegetables are an excellent source of both calcium and magnesium and other essential minerals.
Whole grain products and soy contain relatively high levels of phytic acid which can inhibit mineral absorption, especially calcium. You may want to limit your intake of those foods.
If you are going to supplement with magnesium (400-600 mg/day is recommended) then it would be better to use an amino acid bound (chelated) magnesium such as magnesium citrate which is much more easily absorbed than magnesium oxide (commonly found in multi-vitamins).
I would research Fosamx thoroughly if you are going to continue with this treatment approach. Here is some info on Fosamax if you are interested: [url="http://www.mercola.com/2000/aug/20/fosamax_liver.htm"]http://www.mercola.com/2000/aug/20/fosamax_liver.htm[/url]
Alan