Close to the Mall, but on the opposite side of the Arno, this place is well signed off the SR69 after you've exited the autostrada. Call ahead to check hours, as they can vary. Stocks mainly accessories, and pricing isn't as keen as it could be.
If you do want to do it by public transport, catch a train to Rignano sull'Arno, and from there it is about 4km south.