I like the pond plants idea best, and you could plant things like water iris that don't need to be growing in water all the time, but they do like wet feet just fine. But you're right, your main concern no matter what you do is to keep moisture away from the wall of the house.
The other option not mentioned yet would be to just remove the brick wall of the bed completely. In your pictures it looks like it's not in that great shape anyway. Is there a young man with a strong back you could hire? If you must have it there to keep the look of the house symmetrical, maybe re-build the brick wall of the bed with some drain pipes under the wall, heading out away from the house.
