What you actually want to do is use your n834 as a AP the term repeater generally means you take a in a wireless signal and retransmit it out.
First hook the power line to a lan port of your new router and then hook a pc to the one in the other building to make sure you have the powerline device working properly and you are getting the performance you expect.
After this is it standard how do I use my router as a AP solution except you are using powerline for the cable.
You disable the DHCP on your remote router
You set the IP address to something within you main routers subnet but not conflicting with anything.
You generally use a different radio channel as the main router then you can use the same ofr different SSID and password
You plug the cable into the LAN port of the remote router...ie your routers are cabled lan-lan via the powerline.
should be all there is to it.