Did you check APN and dial number with Telstra? Try to input them manually. http://www.tp-link.com/en/faq-400.html

You just need data transferred in local network between computer and smart TV, right? The TV has to connect Wi-Fi of WR1043ND? As you said, it won't connect, any error message? IP settings on your TV...

Write the thread in English pls...

Not sure if it can be fixed but it deserves to try,,, Upgrade the latest firmware, reset and reconfigure it.

When it disconnects, neither wired connection nor wireless connection will work, right? Can you ping google.com or ping 8.8.8.8 when it disconnects on your PC? Try to Set DNS server manually with...

Check hardware version and firmware verison of your WR841N. If there is an update, upgrade the latest firmware. Reset and reconfigure it to check if there is any improvement. Provide screenshots of...