To get a better answer, it would help if you indicated where you're located, and if the buyer is going to have to manage a flight of stairs or other unusual delivery details to move it out of your home/yard.
Also, which finish and cabinet style? I'm pretty sure, but not positive that it uses a Renner action in that time period, and you might want to mention that in your ad.
When was it last serviced? If the answer is >6 months ago, I'd suggest having it done, since buyers of better quality pianos expect that, and it can generate a technician's report which you can share with potential buyers. "Tuned 3-4 years ago and still sounds perfectly in tune!" won't cut it with a knowledgeable buyer.
Is the matching bench adjustable or fixed? That's also worth mentioning if you have an adjustable bench, since that is typically an extra-cost option.
I typed "charles walter" into the search here, and this is what it returned: classifieds link
You can also try searching the classifieds at the Piano World site and an "all of craigslist" sort of search, if you're willing to wade through some spam. This piano is going to compete favorably against 45-48" pianos from well-known Japanese makers, so you may want to keep used prices of these instruments in your market in mind while you price your piano.
Hope this helps.