Congratulations!

I don't know how handy you are, but there's a few discussions on here about making covers.  There's one idea To make a plexiglass box to cover, kind of like a museum display, almost.

I've gotten some clear plasticy stuff at Joann's and I'm going to attempt to sew a cover for my Woodstock.  Right now my craft room is in shambles because we've had the entire downstairs repainted, but once I get it back together I'm going to try to sew a clear flexible cover.  I can imagine with something like that, you could even put some elastic in the bottom so that it would fit tightly to the typewriter and keep even a determined kitty out. The clear flexibe plastic was very inexpensive, I think about $2/yard and 48" wide.

Which model are we talking about? If it's a portable you could always either just leave it in its travel case, or just use the travel case lid to cover it. If it's a standard you can buy generic typewriter covers still; there's another thread (topic) here somewhere with links to a vendor.

I'd invest in a soft cover for the machine instead of dealing with the ribbon every time you're not using it. Cat fur is not something that you want in a typewriter anyway, nor the inevitable scratch marks from the cats claws as it climbs on the machine. And even if you don't want to buy a proper cover, I'm sure you could come up with some other creative solution like a draping a decorative pillow case over it.