Not quite clear what you mean by window stool. Is it a freestanding stool, or is it more like a bench below a window or in a bay, or recess in the wall with a window in it, and a space for a bench?
If it's a bench a simple roundover is all you need to just soften the edge. You can do the same for a freestanding stool. The roundover keeps the sharp edge from digging into your leg, and reduces the chances of dents, or at least minimizes their appearances.
I am concerned about your bit. It is obviously quite old and it has rust on the shaft, which makes it dangerous to use. I URGE you to buy a new bit and toss the one in the picture. I also suspect that your collet is rusty as well, in which case it should be replaced. You can try removing the rust from the collet if you can't find a replacement, but do it chemically, dry it thoroughly after a final rinse with spirits or denatured alcohol. Here's a picture of a collet that's in working condition. Compare this to your collet:
Collets are extremely precise devices. As you tightening the nut, it presses the collet into the spindle at the end of the motor shaft, which contracts the collet slightly. The difference between a loose vs tight collet is a matter of a few thousandths of an inch. If they are rusty or even pitted, you can't count on their holding the bit. Believe me, you Never want to be anywhere near a loose bit that's spinning at 20,000 rpm.
If there are collets available for your machine, check with the manufacturer if they are still in business first, then try ereplacementparts.com. If it's not there, then you have an orphan, with parts that increase your risk of serious injury. Although it seems expensive, this is one reason most of us wind up buying new routers, and in my case they've multiplied over time like bunnies. Two Bosch 1617s, a Bosch colt trim router (great for small roundovers cut in place), and a Triton TRA001 in my table (3.25 hp!).
Bosch has a superb reputation for customer service and quality products in the U.S. They continue to produce small parts long after a model is discontinued, and the parts are easily found. The problem with some of the off brands is they are made in factories that only seem to produce just enough for the run of the tool. It's all about price so when another maker gives a lower price, there's no incentive to continue making spare parts.
Finally, if you're talking about the trim around the window, you can find that stuff pre milled at any big box store. They have trim in all varieties, from plain to very doggone fancy.
This has gone long but I was very concerned for your safety when I saw the picture of your bit and what looks like the collet. A new roundover bit is not very expensive, but please don't use that collet if it's rusty or pitted.