Hi Lisa, Welcome aboard. Nothing to do to join except to start posting 
Sorry to hear about your arthritis. I deal with that myself. In fact I'm just finishing up a particularly painful bout with my achilles brought on by my arthritis. ( Psoriatic... more about that in a minute) The first thing I would say is talk to your rheumy. Most likely they will tell you running is impossible but you can push. the big question you really need answered is if you run will it cause injury. If he/she says "No, it will probably just be uncomfortable/painful but won't actually damage anything." then you can make the decision on how much discomfort you can stand. (Obviously, is they say running will cause increased damage, and possible hasten your surgery, then it's a totally different story.)
If you have access to an elliptical machine, they are a great way to get the aerobic benefits of running without the joint stresses. Either way, I'm sure your doctor will tell you what mine said, once you start dropping a few pounds, everything gets easier on your joints.
The other option I personally encourage is to explore barefoot running. I know it seems counter intuitive, but trust me, do some reading. Although I rarely run truly barefoot, mostly in my vibram Five Fingers, the one thing that barefoot running does is force you to run gently. You learn to minimize the impact forces and what little you do experience is absorbed by your muscles instead of your joints. There are hundreds of stories you can find of people with arthritis, even full knee and hip replacements, who began running again after discovering barefoot. There are some great studies available as well.
Good luck!
As for me, I've finally gotten back to running, did 20 minutes on Friday and 25 minutes this morning at a lazy 4.5 MPH speed on the "dreadmill." For those few who might remember me here's the update....
The achilles still hurts. I did 2 months of 3X/week Physical therapy which helped a lot with what turns out was significant loss of strength and flexibility after 6 months of favoring that leg. Which is great. But as I said, still hurts and still has a big lump in the tendon. My doctors and PT are confident it's not damaged, just inflamed. So I was given the green light to resume exercise. basically it appears to be another lovely side-effect of my Psoriatic Arthritis... I get the Psoriasis, of course, plus a little treat called Reynaud's Syndrome, and now this swelling of the tendons and Enthysitis, swelling of the tendon sheaths. Lucky me! LOL
My Rheumy switched me to a new med, Humira, about a month and a half ago, so hopefully that helps push some of the new symptoms back into remission.
Until then, I've decided that I can handle the pain, and as long as I leave time to ice after my runs, and remember to do my stretches 3-4 times a day, I should be able to manage.
Great to see this thread still trucking along. Hope to get to know you all some as I start pushing forward yet again!