Much better with homeplugs as said above or an ethernet cable direct from the router...if both these options are not viable then give the amiko wifi dongle a crack...they work ok for minimal data but not sure how it would be if you are streaming large amounts of data !
I couldn't get my dongle working so decided to spend some well earned cash on homeplugs which work just fine for me. A friend had an issue with his, think it was related to switching on the ring main so he ended up investing in wifi extender.
Glad you got it going,...homeplugs only work on the same ringmain so if its a big house with 2 different circuit boards or an extension with another ringmain as you say and homeplugs is seperated between the 2 it will never work as the electrical supply is used within the home to supply a harwired ethernet supply.