Cat pees on clothes vrs the litter box?

so we got a new dog have had him maybe 2 months now. we have 2 cats and they most say upstair the dog is downstair has the living room he is gated in that room so he wont go after the cats. we have the litter box down in the basement and the way the house is set up they walk down the upstairs stairs walk down a hallway and then the ceiler is their. dog cant get them but can see them my 1 cat refuses to go down stairs to use the litter box so she will do her stuff upstair either on my our my daugther clothes..HELP what can I do. and getting rid of any pets is not an option