As near as I can determine there are three options. The first and likely the least expensive (and of shortest duration in terms of life) is to have the folks that repair or redye leather seats for car dealers do their magic on your seats. They match your color exactly and literally apply a new surface finish. Like putting on a new paint job.
That is relatively inexpensive and depending on houw the seats are cared for can last for several years.
You can have the existing seats reupholstered. That might prove to be more expensive than buying new ones and you will have to shop around to make sure you are getting a good price and the folks doing the work are qualified. You may choose to replace the foam or at least return it to the original condition with some additional foam.
The final option is to replace the entire seat. There are a number of manufacturers and I suppost the best way to determine who they all are is to contact your converter, or other converters or do a Google search.
I would start out with the first option and see how that looks and how long it lasts in use. In the meantime you buy yourself not only improved seat appearance, but time to really research your other options.