My answer will focus on the joint pain. Leg cramps can be due to one of many conditions and I do not have sufficient information to provide any guidance. I recommend that you see a health care professional for your condition. There are natural therapeis that can be recommended for treating the leg cramps. You can also contact me directly at email@example.com .
In the case of joint pain, there are several causes which ultimately would affect the recommended treatment. For example, different supplements would be recommended for osteoarthritis than rheumatoid arthritis. There are quite a few herbal anti-inflammatory agents that can be used. These include: Devil's claw, White willow bark, Turmeric, Meadowsweet, Common Figwort, etc. A health care professional will recommend a specific herb or blend of herbs based on their experience treating your condition. The amount of active ingredient will also be important to obtain adequate relief; therefore, you need to ask them to recommend a brand to you.
In the case of osteoarthritis, I would also recommend including chondroprotective (glucosamine, chondroitin, MSM) supplements as these have been clinically shown to help reduce the progression of the degenerative condition. SOme companies have launched a formulation containing NEM (natural egg shell membrane). NEM has been shown to help relieve joint pain. Genuine Health has two products on the market called: Fast Joint Care+ and Fast Arthritis Relief+ (http://www.genuinehealth.com/catalogsearch/result/?q=NEM