I like your passion. Here are a few notes.
The languages you are asking about are all used for different purposes.
XHTML and HTML5 are very similar. You shouldn't have a problem learning HTML5. They are both used for document markup.
If you want to develop dynamic websites, then you will need to learn Javascript. It's the accepted standard for client-side scripting (scripting performed by the user's browser).
PHP is used for server side scripting (scripting performed on your web server). PHP (or Perl, Ruby, ASP.Net/C#/VB, etc.) is used to generate dynamic HTML content, access databases and perform other "domain logic" or "business logic" at the web server.
I would recommend learning in this order: HTML, CSS, Javascript, and then pick any server-side language you like. PHP is popular. ASP.Net with C# or VB is also popular, but may be difficult to jump into directly.
If you plan on creating dynamic web pages that retrieve and store data in a database then you may also want to look into learning a relational database definition and manipulation language like SQL.
You may also look into learning a graphic editing tool, like Photoshop, Expression Studio, Gimp, etc. To create simple images for your websites.
If you study anything for about 2-3 months you'll become competent. If you're learning several things at once, it may take a bit longer. For example, if you learn HTML, CSS and JavaScript together, it may take 6 months before you can create substantial websites. There is only so much time in a day, and you can only divide your time so many ways. It may also be more difficult to learn certain things together as opposed to separately.
Programming in general is a never-ending learning process. It's hard to judge what is "good", as it is a relative measure. Mastery (and I use the term loosely) of anything will take years (see: "Teach Yourself Programming in Ten Years" - http://norvig.com/21-days.html ). You should be able to put together a website in HTML and CSS within 2-3 months, but gaining real expertise with HTML and CSS (especially CSS) will take at least a year. Javascript will take a few months also, but JavaScript will continue to challenge you. It's a quirky language especially working with the Document Object Model (DOM). Once you learn a programming language, learning other languages becomes easier. So after you learn JavaScript you should be able to learn PHP or another server-side language in under 3 months. Again, mastery is difficult to attain. You usually won't feel like you have a good grasp on any of these until you've been using them for at least a year.
I think after about 6 months you can start making some money. You should feel comfortable with HTML, CSS and some knowledge of JavaScript to make simple websites for those in need of simple websites. You can lookup local businesses online and see if they have a website. If they don't, or have a bad one, then you can contact them and offer to build them a new one for a small price. They'll be happy with an inexpensive website, and you'll be happy with new challenges and learning experiences.
Keep in mind that my time frames are not exact. Everyone learns at different speeds and you may have interruptions along the way that force you to take time off from learning.
My best advice is this: Online tutorials are great for learning short, focused concepts, but ultimately fail at providing the necessary foundations for continuing programming education. You don't just want to learn programming languages and how to build websites with them. You want to learn how to solve problems and how to structure/design applications to solve those problems. I would recommend investing in books for whatever you want to learn. They are typically long and can be a bit boring at times, but you come out with a much better understanding of concepts than if you had used a tutorial. Amazon has tons of programming books.
How much time you spend each day, or week is up to you. You will only become as good as your efforts. Musicians typically practice for at least an hour a day. Better musicians practice for 2-4 hours a day. Great musicians practice constantly, but they have no life. You have to balance it. You may find some days you spend 6 hours at the computer because you get "in the zone" trying to solve some problem. Other days you may just need a break. I would say at least an hour a day though.
Good luck!