Rov, just for clarity.
Tamiflu - neuraminidase inhibitor - can prevent influenza A or B infection in those uninfected, can mediate the effects/symptoms of a flu infection, and can aid in preventing the spread of infection.
Tamiflu is a generic anti viral medicine.Its main purpose is both mediating the symptoms/effects, thus indirectly reducing any severe or even life threatening events, and retarding the spread of a virus throughout the population.
A vaccine is NOT antibodies to the virus - its is ( in this case at least ) components of the virus itself, diluted and attenuated.
When injected into the body,it stimulates that persons immune system to produce antibodies to those specific components, and hence the relevant flu strain.
There are problems however - we still do not know how well the components will thrive in eggs ( which is how the virus particles that will comprise the vaccine is multiplied), so we still dont know what sort of yield and hence quantity of vaccine we will get.
Neither do we know as yet how many injections will be required to induce the immune response - It most probably will be one, but it could require 2 shots.
And finally, as others have already commented, it is possible the strain will mutate, and so the components selected may not be so specific.
So, it is very optimistic to say that the vaccine will be ready in 3 months.
That is another very good reason for Tamiflu - to slow the spread of the infection down whilst the appropriate vaccine is completed.
Finally, the other reason we were so well stockpiled with Tamiflu was not specifically because of the swine flu pandemic, but in response to previous and potentially far more deadly scares, such as SARS and bird flu.