Redirecting traffic

My original url is globaldrugdebate.com with shared hosting. I’d like to redirect all traffic from my rooted url globaldrugdebate.com/wordpress. My reason is that I’m being told by my hosting company that I can download a new version of wordpress and change the root url to .com, but will lose everything from the other version. My site is really new but I have some comments and posts that I prefer to keep. Is anyone familiar with the code I need for the redirect?