Help - Issue - Comfast CF-WU810N V2.0 on Raspberry Pi 2

I’m a newbie. I recently got a Raspberry Pi 2, and then I’m trying to use Comfast CF-WU810N V2.0 with my RPi. I’m also using a Amkette wireless USB Keyboard/mouse with Raspberry Pi 2, along with this Comfast CF-WU810N V2.0 dongle. My problem is, the WiFi signal drops out very often and also, the signal strength is too low.[2% it shows almost at all time] Sometimes, when I disconnect and reconnect the WiFi dongle, the signal strength suddenly rises to 80% or more, but eventually, it drops out in a few minutes and the WiFi signal goes out completely. I am using a 5V, 2A charger which came with my mobile phone, but still using a 2A power supply doesn’t solve the problem.

What might be the reason for this low signal level and dropouts? Is there anyone using Comfast CF-WU810N V2.0 with Raspberry Pi 2 without any issues? Pls help! :disappointed:

i am also using this USB WiFi and unable use with raspberry pi can you give suggestion which is most useful USB WiFi for raspberry pi