Do you have link 100Mb/s or 1Gb/s from router (please see network card)? Can you check connection on another cables (patch cord)?

when i am using my TL-WR1043ND router in the middle to split the connection and wifi etc its giving me speed as 9mb only Is this wired connection between router and computer? i am getting pure 20mb...

Your main router?

I suggest you disable the hardware NAT then try again. I agree, please try.

Please report it here - http://ticket.tp-link.com/index.php?/Tickets/Submit

Give us screenshot from status and wireless settings tab.