You can't go from wireless to wired. It's not even apples to oranges but more like apples to radiators. You'll have to give up that avenue. The best that you could do is set up a AP via ethernet near your wireless device. That would convert 802.11(wireless) to 802.3(wired). You could also go with a wireless repeater too if distance is your issue.
A bit more detail on the device and the issue to overcome would allow us to provide solutions that could work for you. Unfortunately a dongle or wire adaptor from 802.11 to 802.3 does not exist nor can it.