The way we are dealing with the bat is this: we bought this thing that makes a horrible noise, constantly. It's called, "psychoacoustic jamming". It's supposed to work to keep out rats, mice, birds, bats, hippies- you name it. Every time we leave the house for an extended time, we turn it on. The idea is that the bat will hate the noise and find someplace else to live- like one of the two nice bat houses we bought and placed outside the house and the barn. So far, I don't know of it's working.
"Psychoacoustic Jamming" is also a synonym for, "Lee Family Reunion".