Adding Blog To Pre-Existing Website

I have a preexisting website with it’s own CSS, look, images, etc.

What I want to do is have wordpress handle my articles/blog, but maintain the look of my website. I tried this before and got it to work… a bit… but certain things, like categories, the archive, etc, disappeared and I couldn’t figure out how to get them to work.

Is there a “How to” regarding how to do this? Or could someone direct me to the (no doubt) many articles I’ll need to read in order to do this?

My PHP coding skills barely involve knowing how to call something (like my header, side bar, and footer, for example. XD), so please bare with me.

I’m planning on including the Comic Planner add-on as well with this, and hope to have the comic in a separate directory from the blog itself. So, site.com/comic-page/1 and site.com/blog/2008/08/Title.

Is it possible to do this in the same WordPress install, or would I actually have to have two separate WordPress installs?

And finally, I’d like to have a dynamic blog post on my non-wordpress index page, so the first 1-3 blog posts appear on the homepage. Thought I’d throw that in, rather than make another topic. (This was suppose to be a short post! ><)