A couple of questions.
1) Do you own a domain (xyz.com)?
2) Do you have a web hosting company?
3) If you don't have a web hosting company, then does your computer have a fixed IP?
Once you have a domain, the company from which you purchased the domain will allow you to specify the IP to which the domain should point. Given your stated limited knowledge, I would strongly recommend a web hosting company until you are comfortable enough to choose an alternative solution. A large, inexpensive company in the US is GoDaddy, but there are many others, a number that are cheaper, etc. When selecting one, it helps to know which version of PHP, Apache, MySQL, etc. they run as they are often using older versions (GoDaddy is using PHP 5.2.8, but the current version is 5.3 or better.
To deploy, make sure you get a linux box (vs. microsoft)
Once you have some answers for the questions, I might be able to help you a little more.