Hi genepitts, I’m not very familiar with Contribute, but you’d be welcome to move the site here.
I’d recommend bringing in your content first, as posts or pages. If you can export the site, great; if not you can copy and paste content into an editor — just use the HTML Drag and Drop method mentioned here: https://transferto.wordpress.com/
Do you still have access to the domain and what not? Also, can you tell us what the existing site is?