This is what I want to do, create a new theme... Can I do it?

I'd like to create a new personalized theme for my investing website, www.eafepro.com.

Right now I am using a contributed theme that is great, however is lacking on the home page. I need to create multiple blocks on the homepage that will list recent nodes (be it blogs, pages, stories, or forum posts).

I'd like drop down menu links.

I've created a template in HTML/CSS. How can I port this? Or is it easier to use a subtheme and copy/paste the code over? Can someone offer advice?

It is for the investing website, www.eafepro.com. It is meant to be a community for investors interested in the EAFE, i.e. excluding-US markets and various emerging markets.

Thank you.

Owner, eafepro.com
Owner, CWFEU.com