uhhh...use extra planetary launchpads to build a (MASSIVE)rocket to fly away to the outer reaches of the kerbal galaxy so we dont get destroyed by the supernova, but like a used to be shuttle launch, the closer you are, the differenter death you shall have, so if you are within a few-tens of lightyears away, the radiation would hurt you, but the closer you get, the more radiation you get, and may get an extra set of ears, who knows
but if you are in the kerbol system or Kalpha Centuri (closest star to kerbol) then the shockwave (or something like that) would rip you and your planet apart.
so we have to have a massive MASSIVE MASSIVE amount of DELTA-V to get out in time, or we could download a mod like hyper edit and forget all of the thinking
so we have to do either hyper edit (THEY DO USE HYPER A LOT!) or go the kerbal way and make a massive rocket