Advice about starting from scratch

Hi all, I wonder if anyone can help. I would like to (slowly) rebuild my website in wordpress. It’s currently just built in html with a few wordpress sections and I would like to start by finding a theme that I can roughly replicate the homepage in. I figure that once I do this, I can have it live but still link to the existing sections, and gradually replace them all. It’s going to be a big job!

My website is http://www.essexmums.org. I would like to change the homepage a little so that it’s neater, with images and a little wording that link to each section, so am not concerned if it has to change a little, but want the header and ads down the right to remain the same.

Can anyone recommend a good theme to start with? I’ve been looking around but have struggled to replicate it.

Thanks