Site Migration (OSCommerce - Opencart) To Check all SEO aspects

We've recently developed and migrated our old e-commerce site from oscommerce into opencart (latest) version. We've got SEO URL's too extracted for the new site. I'm looking for an SEO expert who could look into it, ensure all SEO related things covered into our new site, assist overall site management to ensure new site holds all Key SEO things that already built with old site. This is part of first phase of tasks. So then we can march into improving SEO aspects with current site which is the part of next phase.. We have very short turn around time. So, If you're available to kick start immediately would be much appreciated.

Brief your expertise, any samples along with our queries pls..

Lastly we are thinking over long term support expecting to handle the site in terms on SEO related activities.

Best Regards,
Raj