Unfortunately it's not really and easy process. It's not about just having a table. The tables in WordPress will have different names, fields, and relationships than the cms you're pulling your table from. That's just for the content. Then to mirror appearance will definitely be starting over all the same.
It would likely be a much easier process to create a new wordpress install with a clean install and manually set up new pages with the old content.
Without knowing more about your current CMS or how much content you have I'd strongly suggest you go this route. Sorry for the bad news, but good luck and you'll love wordpress.
UPDATE BASED ON COMMENT
While by no means an endorsement, you may want to check out wpallimport. It will let you set up imports based on CSV files and let you import them into any post type. It doesn't have that steep of a learning curve, but it will even let you attach photos to the posts to update!