Hey Breed,
You are where I was 2 days ago! LOL...
You don’t need to recreate... IF you are handy with code, especially CSS. (I am dealing with a crash course currently)
The key is that you are unlearning a few ways of looking at sites.
MODx is based on TEMPLATES rather than "pages" or "layout". With that in mind... easiest (and overall messiest) way to deal with your issue is to take your pure HTML/XTML code and paste it in the "Document Code" area of the "New Template" form.
From there you begin to deconstruct and or replace...
There are two tutorials in particular that are hugely helpful for this stage:
Everrett’s video series:
http://www.tipsfor.us/2009/01/22/new-overview-of-modx-modx-series-part-ii/
And Mary’s blog based howto:
http://codingpad.maryspad.com/2009/03/28/building-a-website-with-modx-for-newbies-part-1-introduction/
They will get you up to the "I have imported it and started messing with functionality" stage.
Enjoy!