You should have 2 instances of your website. One being the development(the testing server) and one the production (the one the world sees). Typically, these are hosted on two servers with identical LAMP/WAMP configurations. You may want to set your "hosts.allow" setting to only let in certain people and block everyone else from your development server. I'm sure other people will have more information, but this will give you something to think about.
yeah i know what you mean. i've only been on this for around 2 years and i've learned alot and keep learning more everyday! in regards to your question about moving tables, i think the best way is to do a mysqldump and copy your entire table schema into your target database. phpadmin should have something like this - although i haven't used it (i just ssh into the database via telnet client). good luck and have fun
Do I need to change all the php code to now reference the host's server location?
It's definitely worth considering splitting your code down into include files if you haven't already. That way when you have to make a change to something you only have to do it once rather than multiple times. The connection to your database would normally be in an include file for example.