Do any wireless headphones for a deskphone exist that will give you range beyond 300 feet?

I'm looking for a wireless device or adapter for my office deskphone that will allow me to travel into another department probably 1000 feet, and still maintain clarity. The only wireless headsets I've been able to find guaruntee clarity for 300 feet. Does any company make a headset with further range or even an anntenna or device to boost your signal as your get further away (like a repeater for radios)?? Thanks!