Recording sound from 35 feet -- as in the sound is 35 feet from the mic -- is basically infeasible, unless you're in EXATRREMELY quiet surroundings, like underground.
A shotgun mic won't help a lot. Shotguns aren't magic, and in particular are nowhere near as directional as people imagine. Look at the detailed polar diagrams for a shotgun, broken
down by frequerncy, and you'll see that at human voice frequencies, they're not much different to cardioids.
But you mention wireless. Unfortunately you don't say what kind of audio you're trying to capture -- is it a person speaking, by any chance? In which case a wireless mic is the easy answer. Just clip a wireless transmitter to your speaker, and plug the receiver into your camera, and you're good to go.
There are MANY wireless systems on the market that will work with the XA 40. Since the camera has both XLR and 3.5mm, you have all the options. Just google "canon xa40 wireless mic", or "canon xa40 mic in", to find some videos that might help.
