Antique Platform Rocker

I've just astarted collecting antiques and purchased this chair because I love the era. The wood is oak, I think. The upholstery has been redone, obviously. I want to redo it and make it look like the original. One of the long back spindles has been fixed with some sort of dowling, not sure if it was wood or metal. It was done professionally as I almost missed it before I bought it. (actually I did miss it, my daughter pointed it out.) The springs need to be replaced as they are very loose and if you try to rock in it you will tumble backwards. Just wanted to know what it is actually worth, (I don't want to sell it) and what type of fabric do I need to redo the upholstery? I know it's also known as a carpet rocker but what kind of fabric would that be in this day and age.