WiFi Having Issues with TP Link WA 901ND and Cisco Wireless Router

I recently added about 1200 sq feet to my house and noticed a huge drop in wireless access throughout the new part of the house.  The Cisco wireless router is in my basement and until the new part of the house was built, it worked perfectly.

However, the farther I traveled from the router, I noticed on my iPhone that the signal got weaker.  As well as my iPod(s) and iPad.

After doing some research, I decided to go with a TP LInk WL TL WA 901ND 300Mbs AP.  Setup as a an access point and used the same SSID and password as my cisco so that my devices would not get lost or confused. Well, I'm thinking that's not the case.  I noticed last night that even though my wireless strength on my iPhone was strong, it was having a difficult time trying to browse sites or go on social media.  Like the phone was connected but couldn't get through.

The TP link is setup as an access point with a fixed ip and the gateway is set to 192.168.1.1 which is the router gateway in my basement.  The IP address of the TP link is 192.168.1.254 whichi is a factory default and no other device on my network has that address (although I should double check to make sure).

Any other thoughts/suggestions would be greatly appreciated.  I can attach screenshots if that will help just need to know which screens to attach.

Thanks in advance.