I have arthritis in my fingers and its affecting my writing. What do you suggest I take to help?

NSAID meds. Like celebrex, (celecoxib) naproxen, ibuprofen, etc., can help. Physical therapy can help sometimes, cortisone injections, compression gloves are some other options.
Less mileage. "arthritis" most commonly means degenerative joints, as opposed to rheumatoid (a positive blood test). Management is different for each. Assuming yours is degenerative, one way to protect your joints is to decrease the 'mileage' you put your hands/fingers through. There is good data about joint-related benefits of glucosamine/chondroitin. Otc meds can help but check with your doctor first.