I have an airport extreme and express setup. My extreme is in my 2nd floor office with windows facing the water. My dock is about 250 ft away down a very steep hill. I have the express about 100 ft down the hill in an electrical waterproof box attached to a tree as high as I could install. The signal is weak and I'm thinking I might have to buy another express. Any thoughts on the best setup for me. I ultimately want to control speakers(hard wired in) down at the dock with my iphone. I have a receiver coming with airplay built in.