If you have an existing corporate website with established pages, established search engine optimisation and possibly an existing content-management-system (CMS) installed, then how can you have a hosted online shop like Ozcart™ as well?
The good news is that it's easier than it sounds, providing the hosting provider of your existing site can set up what is called "delegation" for a sub-part of your domain. An example of the end result in action is HSV, who maintain their own website platform and run an Ozcart online shop to sell their racing apparel merchandise.
The colour scheme and imagery can be aligned so that your shop has its own feel, and is still a standalone website in its own right, but feels like it is part of your website "family". That is, it includes your business name, logo and imagery if appropriate.
Setting this up involves setting up a subdomain like eshop.hsv.com.au (this can be whatever you want it to be) and pointing it to a particular location on the Internet - we'll tell you what to ask your hosting company to do. The Ozcart shop then has it's own admin facilities and own is a standalone shop but doesn't affect the rest of your site. You can just link to it on your main site, as Holden have done for their separate Australian and NZ shops on their HSV website. You can also point other domain names to it, or your blog, if you have access to them.
So even if you have your own existing website, you don't have to get rid of it to add online capabilities, you can run a shop in parallel to your main site and link it into the family.