Tamiflu doesn't really cure flu.Its mode of action is to stop or slow the replication of the virus. There is a degree of protectionism in its action since it can prevent the spread of the virus to other tissues. and therefore spread of flu throughout the body. It will therefore be most effective when taken early, after you have become infected.
So the design and action of the drug is to reduce the symptoms of the disease, slow down the replication of the virus, and prevent the spread of the virus, so minimising the effect of the flu.
It may therefore be the case that the Tamiflu course you have taken has in fact worked and reduced the symptoms of the swine flu you are experiencing.
You dont say how long your course was, but in many cases a more prolonged course of the drug could be beneficial. I think you should certainly contact your GP again and get their advice as to what , if any, additional treatment might be required.