I encourage you to vote next time. Of course no party will ever be fully aligned with your interests. And true, the Pirate Party has only recently started to seriously think about topics outside their main fields. But no party completely pushes through their own positions anyway:

If the Pirate Party would form a coalition e.g. with the Union party, they would have to negotiate a coalition agreement. And each party will make sure that they please their clients (i.e. their voters or other supporters) sufficiently. So the Pirate Party would probably abandon their weaker positions (e.g. economic policy), but hold their ground on their main topics (copyright/patents etc.).