Not sure where you can donate, but my cat had a similar issue. I ended up getting a litterbox that was actually intended for small dogs. It was bigger than a cat litterbox (let her take a nice wide stance), and the front lip was only like 1.5 inches tall (and very wide, useful later on when she stumbled). They don't make the one I had anymore, but don't just limit yourself to cat boxes - a dog box might work too.