Wireless Network Extender With LAN Connection?

my bt home hub is a far way from my desktop pc. i was using a old wireless network adapter to connect my pc to the wireless connection, it was slow and would always drop. today i brought a high performance gaming network card for my pc( just lan no wirelss), and i also brought a tp-link 300mpbs wireless N access point,i had the idea that i can use the extender to pick up the network, then run a lan cable from the wireless extender to my desktop pc, the guy in the pc shop told me this would work.ive been working on it all day and cannot get it to work, ive used different settings such as client mode,bridge ap mode and repeater mode. i also made a static ip, when the tp-link is plugged into the pc, i can ping to it, but when i try one of the connections. i just get unidentfied network - no internet access. i can connect to the tp-link via wireless with an adapter but i wanted to make use of the network card i just brought!