Maybe I'm confused, but if your goal is to build a Web directory, CMS, or any other substantial PHP app, plan on spending a
lot more than three months on it. I only say this because when you set your goals unrealistically you will get frustrated! Believe me, I'm working on my third CMS.
HTML is a markup language. PHP is a reflective programming language. Many differences here. You should spend at least three months getting to know the basics of PHP. I've been using PHP for 5+ years now and I still learn something every day. And this with a previous programming background in C and Perl.
That said I would start with a basic project and use Google and your reference books to work through it. For example, connect to a database, INSERT a record, SELECT that record, then display it. It would probably be very helpful to read up on basic programming concepts as well; you should be familiar with conditionals, control structures, variables, constants, operators, functions, and basic PHP syntax.
There are a multitide of sites out there with PHP lessons. I remember using phpbuilder.net quite a bit. php.net and Google are your best friends though, never forget that! The PHP documentation should never be neglected.
Regarding developers, well there are a plethora or forums with eager developers looking to make money, as well as scriptlance.com and others. When you do hire, start out small and build up a relationship with your coders.
Not sure if this addresses your questions exactly, but I'm happy to help out in any other manner possible.
Good luck!
Gabe