TP-Link TL-WR1043ND - Extend Network Via Power Line Adapters Or Second Router

My situation is as follows: A modem in the hallway closet with an internet connection via a coax cable. A living room with an i Mac and a Philips PFL9604 TV connected to the wireless network. The wireless network is provided by a new TP- Link TL-WR1043ND router which is setup next to the modem.

I would like to do the following:
Stream content such as HD movies, shows etc from the i Mac to the TV. Use the TV to watch missed shows with the apps on the TV via internet. Make use of the internet speed upgrade (75 - 150 m bit/s) which will come in a few months. However the signal of the router currently isn't strong enough to maintain a stable connection since it's too far away. The distance from the router to the TV and the i Mac is 12 meters and 6 meters with a wall in between as well. Now I can't move the modem from the hallway closet else the signal to the modem will be too weak nor can I wire an utp cable from the hallway to the living room and put the router there.

I have come up with two possible options now:
Use power line adapters by plugging one into the hallway socket and one in the living room so I can put the router there.
I currently have these power line adapter to try out, however my internet connection occasionally drops while using these adapters. Take the old WRT54GL router or a second TP- Link TL-WR1043ND and use WDS to create 1 network and have good coverage in the living room. The i Mac and TV can then be connected via Ethernet cables to the second router if necessary. I assume it would be best to place the second router closest to the first one for the strongest signal.

The second options seems the best to me as the power line adapters don't seem very promising based on my experience so far. I would like to know if connecting two routers is a viable method to obtain good and stable coverage in the living room?