I have exactly the same All-in-one, I have set it up Wireless and am totally delighted with it.
I would suggest that you re-install it following the original instructions exactly to the letter. I assume you did notice, that a USB cable is required for the initial setup? Once up and running the USB cable can be discarded.
If you subsequently want to allow another PC to share the Wireless printing, you need to install the original software on that machine as well.
Stick with it, it is one of the best printers I have ever owned, and I have had quite a few over the years, all Epson.