drupal upgrade to website using old version

We currently use Drupal but an old version which we want to upgrade and fix any issues. www.firm-n-fold.com.au I was thinking we could just upgrade to a newer version. We have customization's on our existing website to allow integration of orders into Accentis; our online accounting software program. I wanted to upgrade the shopping cart as well so it is more user friendly ( less clunky) We want the best customer experience and want to reduce abandoned carts. We want to improve CRM & SEO

1. To reduce abandoned carts with automated email stream
2. Automated email stream targeting of people visiting our website with incentives to sign up to our rewards program or special offers on products
3. Ability to add new products or remove them.
4. Add or remove product video’s
5. Add or remove product images or manuals
6. Make sure we can track activity through google analytics and provide monthly reports
7. Develop other ways to target customers visiting?
8. Improve SEO and migrate SEO to new version

I need a rough indication of the cost to do all this?

1. Upgrade the site ?
2. Create a new site?