I've had Rheumatoid Arthritis since college, getting near to 30 years ago; it's general throughout my body, has lead to substantial joint damage, 5 surgeries, etc.
Cure: there isn't one, though most forms of arthritis can be controlled. Joint replacement is an option, but from what you've written, that sounds a long way off -- and it should be kept that way as long as possible.
Pain-killers: Do you know what type of arthritis you have? Osteoarthritis is the most common one, and is the one typically associated with aging, but is hardly the only one out there. If you have osteo, what pain killers you take isn't as important as it is with some of the other types of arthritis, esp. those that cause joint inflammation. Assuming the doctor didn't prescribe anything, with an inflammatory arthritis your best choice is aspirin, because its anti-inflammatory qualities are superior to every other OTC I'm aware of. Tylenol, for instance, does next to nothing for inflammation...
Exercise: Based on my experience (remember I may have a different type of arthritis, but I think what I say is applicable to all of them), slow and gentle is the way to go. When I was first diagnosed with the disease, I frankly was mad as hell about it, and wasn't going to let it stop me from doing things. Among my mistakes was the determination to do exercises such as push-ups. Push-ups put a lot of stress on the joint...I wound up destroying my wrist joints, and it is now impossible for me to do even a single push-up. aerobic exercises -- swimming, bicycling, horseback riding, even plain old walking, are all good choices for gently working all the joints and keeping muscle. If you are concerned about the range of motion in your hip, a doctor can recommend specific exercises for that.
Dancing: keep doing it! It's great for your mental as well as your physical health. But also use common sense, and accept you may have to make accommodations to the disease by adapting movements to your body. You don't say whether your a social dancer or if you're into "dancesport." I'm a social dancer: I'll never be in a serious competition; I'm unable to do all the styling "correctly." For instance, I can't rise up on the balls of feet -- I haven't really got any balls in my feet anymore. So I do things a little differently...my partners don't care at all! If you're competitive -- well, I don't know all the ins and outs, someone else can perhaps offer suggestions on that aspect of things.
P.S. I also got into dancing many years after being diagnosed with RA. And if I can do it...don't let arthritis stop you!
