What can happen if you get the Swine Flu vaccination and you get Swine Flu will you have to get the vaccination again?

Vaccinations work to give you immunity to infectious diseases by tricking your immune system into thinking you have the virus which makes it develop an immune response and make the antibodies you need to be immune. You can also get immunity by having had the infection. So, you should already be immune through both mechanisms, there would be no reason to get another vaccination.

If you had a swine flu vaccination and then got the diagnosis of swine flu, you did not get it because your vaccination wasn't good and you did not get it from the vaccination. You either had the flu before you got the vaccination but the symptoms had not yet shown up, or you caught the flu between the time of getting the shot and when you had achieved immunity from the shot (it usually takes a week or two with most flu infections to develop the immunity).