TL-WA7210N has a build-in antenna that it can cover up to 5km in P2P connection. I think 200m is just a piece of cake for TL-WA7210N.
But if you want to cover more than 5km, you can add a high gain directional antenna or replace the TL-WA7210N with a CPE510/WBS510(They works in 5GHz frequency segment).
About the P2P connection as the below topology
internet------TL-WA7210N_AP mode))))))))))(((((((((((((TL-WA7210N_Client mode---------devices in use,
you should:
1. Mount them up and adjust them to face the target direction.
2. Setup one in AP mode with internet access and the other in Client mode to provide internet.

If you have configure the AP-Client combination of TL-WA7210Ns but can only cover 200m, there maybe sever interference or obstacle in LOS.
For interference you may use a TL-WA7510N since it works in 5GHz with more alternative channel to avoid collision.
And for obstacle you need to mount the device higher and LOS is not enough, 1st Fresnel zone is needed. Look at the link below:
http://www.tplink.com/en/faq-907.html

right now connected single TL-WA7210N device. With the help of laptop i am testing Wi-Fi signal coverage, giving only 200 meters.

two devices are mandatory to get 5 kms Wi-Fi signal covereage???

thank you for your reply. using single TL-WA7210N. tesing Wi-Fi signal coverage with Laptop. two devices are manadatory to get 5 km+ wi-fi signal coverage distance??? with single AP TL-WA7210N what is the signal coverage we will get???

No, you have misunderstood me. A single AP can cover a long distance, whether it can be 5km is not sure. But 200m is easy.
Since 7210N uses a directional antenna with horizontal beamwidth 60 degree, you should be in the coverage area to receive the signal.

Think of it this way, the TL-WA7210N can "shout" loud enough to be heard 5+ Km away but unless the device on the other end can "shout" the same distance there is no connection. So to cover that distance use two to span the distance then other ap's for the devices in that area.