help me with my setup

[Nootey]

Hello!

 

So due to my  house layout i'm rocking 2 routers. 1 is a TPlink WL740N and the other is the one my ISP supplied. I have the tplink in my room as a wifi extender and i have my internet cable in its wan port, the other end is in the lan1 port on the isp router. I get better performance and download speeds if i plug my pc directly into the isp router but my wifi is f*cking terrible. With the tplink i get lower speeds ,not really THAT noticable but its there. But my wifi is still pretty bad, only reaching 40 mbs down 20up from my 100 down 20up connection. It's probably the routers limitation cause its pretty cheap but would you suggest any setups with which i could get better speeds with my wifi and possibly my desktop? I've read some articles on the internet some say to turn off DHCP on the 2nd router but then i can't connect to it via gateway... Any help is appriciated, thanks!

[Nootey]

ah ok, so i can't achieve my speeds with my current router? Well yea i have my setup next to the router, all tho the pc is under the table and the router is sitting on a subwoofer. Could the woofer be causing interference?