it seems a little complicated. can you draw a simple topology and see if someone could figure out the problem

i found this from the website http://www.tp-link.com/en/article/?faqid=258 And you can start from "For All Operating Systems" in the instruction

maybe you can try WISP on the router

The other computer is connected to the BT hub by cable or wirelessly? Normally, the wireless speed will not be able to reach the wired speed because of the interference or something else. You can try...

Do you want establish Soft AP or just connect to the wireless network by the adapter?

is this your network connection: PC ---1043----8960(dial up the internet) ----internet | VPN server 8960 should support VPN passthrough which is enabled as default.and you have set the port...