I am currently restoring an '89 as well that I am documenting here:
https://buggiesgonewild.com/showthre...47#post1890847
Your seats look to be in great shape. You just don't like the color? Assuming that's the case you really only have two options:
1) You can get vinyl you want from a craft store and do it yourself. A few attempts will get you a decent result. There are a few You Tube videos out there that illustrate how to do this.
2) You can take the seats to a professional furniture upholsterer and they can do it. This will get you OEM-like results.