This site is just amazing, full of all kinds of information and tools to help us on our journeys to a healthy lifestyle. Best of all is the caring Community of fellow Sparkers, ready to offer support and encouragement.
Have you checked with your doctor, to see what exercises would be appropriate for you? While we all want to be helpful, we're just "laypeople" and when it comes to a chronic condition, your medical professionals are the best ones to advise you about problems you experience that may be aggravating your condition.
Like the previous poster suggested, there may be a SparkTeam for those with RA and also articles here on Spark about dealing with RA.