Unless you are adept at upholstery, I would suggest finding a shop in your area that does this type of work. A new seat is probably in the vicinity of $700-800 thru dealer. The seat has to come out and the spring pad inside the seat has to be removed to get at the cushion material. Find a pro. If the outside of the seat is still in good shape, you will save some money over a new item.
2000 Dodge Grand Caravan SE
No matter what you fix, there will always be something else to fix..
"Warranty" is just another way of postponing the inevitable.