Build an Online Store - from an OSCommerce Template SSL https://www,thephysiostore.com

I purchased a template from Template Monster: [login to view URL] They set it up under the domain name [login to view URL] under my hosting account at GoDaddy. It originally was not SSL secured. I made some changes and added some content. Some things I could not do. I have since changed the main Domain to [login to view URL] I cannot go into the admin panel anymore... I also made the Domain SSL https; This template is not setup for https and the page is not secured. [login to view URL] I need it secured and running smoothly and be able to log into the back end. I also need to convert this site to a responsive site for mobile use. I need to speed up the site. I need to add some addons - Pages, shipping modules (Canada Post), UPS to the site. I need to have some of the content changed (address on bottom right side of page). SEO work...Not sure what this entails or means but need to increase ranking This site is going to be designed for use in Canada..I am not able to compete in the US. The site will combine sales of products with the professionalism of physiotherapists (physical therapists). Down the road, I want to offer advise, general exercise prescription, andidotes from a physio perspective etc. Q & A on products would be good. I hope to add other things to sale down the road such as health apps, video and exercise program for specific injuries etc.) In the end it might be better to create a store from scratch instead of using the template but the design of the template looks good and I heard OS Commerce has a lot of addons and has been around a while. I need someone who can advise me on this project and help over time transform it into a premier Canadian Online Store with advice from a physiotherapists perspective. I am not convinced this store will take off in Canada. I cannot find anything quite like it. Lots sell products but I want to add the professionalism of a Physiotherapist. I want to start of with a small budget (hence the template) and see if it can succeed. As it does, I hope to re-invest to make it bigger, add additional features etc. Can you help?