Insert my header and footer into the open cart php

General information for the website: Ecommerce Site
Kind of development: Customization of existing website
Description of every page/module: I need help with the store part of a website that is been built basically I`m trying to insert my header and footer into the open cart php, I am using a plugin to give the option of calculating time and another for a fast checkout. I managed to remove it from its original container so it stretches across the page better but would like to set it at 20% each side till about 700px then just make it all 100%. the checkout when installed correctly will scale it self so its just the 3 pages products, selected product and basket. the problem mainly lies with the footer since the header seems to be fine. the footer sits at the bottom of the screen and not the page if that makes sense, it obscures the content, and for some reason when i installed the new footer its also interfere's with the actual open cart pages working.

Can anybody help
Description of requirements/features: insert my header and footer into the open cart php,
Payment methods: Paypal
Extra notes: