Hey, looking good there. Your site is OK.
I reckon that you should think about going to a dynamic website now. This means using a database-driven site instead of HTML pages. The advantage is that page building is easier (there isn't any) and you can do a lot more.
The big advantage that you have is you've done your apprenticeship with HTML, so this is not an unknown area for you, as it is for many DB-driven site owners. That knowledge is useful.
You would have a choice of programs to use, and they are laid in in the
Best Free CMS review - because that's where you are now. A CMS is a DB-driven website. The first step on the ladder is WordPress and you can stay with that in the long term, no question, there are some great WP-based CMS sites out there. In fact I advise this route.
Or you could volunteer for some serious brain damage in the short term and go for a full-on CMS like Joomla. The first month would be hell but after that you can do more with it than any other CMS.
Up to you - but read the review and see what you think.