HI cruizon, welcome to the board
. My first it of advice would be t read the book The Myth of Osteoporosis
by Gillian Sanson. Its a very informative book that will explain about treatment options, diet, exercise and supplements. Then make a list of all the questions you have about osteo and your other conditions and take them with you when you see the specialist. When you first see him tell him you have questions so he'll be prepared to spend the time answering them. Also, prior to your appointment do some research on the drugs for osteo, like fosomax or actenol, and be aware of how they work and the side effects they cause in case that is what the doctor wants you to do. Its important to educate yourself.
You ask about calcium, the best way to get calcium is from your diet, but since many of us don't do that everyday supplements are helpful. Calcium Carbonate, which needs to be taken with food for good absorption is a common one and so is calcium citrate which can be taken on an empty stomach. There are several different kinds of calcium to choose from, but these are the ones most used in OTC supplements. Magnesium helps with the absorption of calcium and can be taken with the calcium. That's how i do it. You also want to get adequate Vitamin D3. With your other conditions your doctor may have other suggestions.
If there is anything else we can help you with just ask. Good luck with your appointment. Keep us posted on how it goes. take care...phyllis