I have redone ours twice. It is a Better Homes and Garden swing that is built very sturdy and I refuse to give in and get rid of it because of the trees, weather, and the nasty squirrels perching on it.
I went to Hancock Fabrics and purchased fabric made specifically for this. It was very simple to take off the old one and make a pattern using it. I sealed it with Atsko Silicone Water Guard Spray from Walmart. Lasted almost 3 years and then I re-did it with a different patterned fabric. Buy the fabric on sale and it doesnt hurt so much....