@SunilAdiraju 

Please help verify some details, and we will try to fix it together:
1. How did you test this Wi-Fi speed via the router? Did you disconnect all the other devices from it and only leave one laptop or phone performing the test? It is suggested to change a new SSID and password and connect only one phone or laptop to perform the speedtest 3 times.
2. How about the wireless negotiation speed on that device? If the link speed is not as good as expected, please try another wireless device with more powerful wireless cards.
3. Please simplify your network layout if there are other routers or RE in your network, just leave the modem and the WR841N on, disconnect other devices and run the Speedtest app 3 times. Please ensure the wireless channel width is set to 40MHz. Here is the guide to modify the wireless settings on the router:
https://www.tp-link.com/support/faq/78/

@SunilAdiraju 

How about the wireless negotiation speed on the laptop? Check it by referring to this article:

https://www.tp-link.com/support/faq/2265/

As you know, 300Mbps is the maximum theoretical speed you can get when your device negotiate with 300Mbps, check this article for more details:

https://community.tp-link.com/en/home/stories/detail/321