Should I keep my Wordpress site or start over?

Hi, I am looking to improve my ranking in Google. I am torn whether to "upgrade" my existing site ( or start over from scratch with a new site and new name. Whichever way I go I want to maintain the site to be SEO friendly. I fear that part of my problem is that I didn't set up the existing site in that way. Any thoughts would be appreciate. Thank you for your time! Steve