One way you have promote yourself as a web developer is by having a well done website. You're website definitely needs work; both on the design and development sides.
I say if all goes well it will take about 3 months to make a basic credible site.
Thanks! That´s not what I´m looking for (that´s in my profile!). I want to show e. g. an example of a (simple) database!
Then make an application that uses a database and then show a link to it. If you make a demo version of it, all the better. From a PHP standpoint, you will want to make a contact form and use PHP to process it so there is your first PHP project. Making a basic blog to add a news type feature to your site would be the next thing to look at.