Travel to China and Taiwan

Dear Sir/Madam

I am an Italian citizen (with an Australian residence) that is currently in Seoul, Korea. I am planning to travel to Beijing and Taipei for a week only from this weekend and I just came to know that a Visa is needed. How can I apply as a tourist? Can i apply for it online? Is it possible to get it in a few days?

Kind Regards
Stefano Raimondi