Hopelessly confused

Sorry about this non programming question but I cannot find a good explaination of what I need. I have VB 6 professional which I have not programmed in for a few years. Can someone tell me what I should get to upgrade to visual basic.net? Is there an upgrade or do I have to purchase the whole thing. Do I just need Visual Basic.net, or Visual Studio.net? Does Visual basic.net come with Visual Studio.net? Do you need or want Visual Studio.net when developing in VB? What about various versions like standard, professional, or what ever?