After 20 years, it just might be time to update completely. I work with plumbing and believe me that valve in the shower will need attending to soon.
if the budget can hold, you could just remove the tile surround and re-tile with a new tile pattern or solid surface such as Corian.

Replacing a shower door and frame is relatively inexpensive and immediately updates.
Plumbing with trim in the shower and at the sinks can bring you to 2013. Please plan on updating to a thermostatic valve. ( check your local plumbing codes. It may be required)

I like Hansgrohe products. Very well made and tech suave designers! A bathroom salesperson will be able to work with you on budget and products. Always purchase Hansgrohe from a plumbing showroom.

Good luck!!