I'd be happy to help you!
So it sounds like there are two things you'd like to do: point your nameservers for your domain to your blog at Wix, and then redirect your current blog to that other blog.
First, you'll want to change your nameservers. You'll need to log into glutenfreegutt.wordpress.com and go to Store > Domains (you'll know you're in the right place when you see two domains listed: glutenfreegutt.wordpress.com and glutenfreegut.com.)
Then, you'll need to look toward the bottom of the page where it says Domain Administration and select "Make changes to DNS" from the drop-down menu.
Next, follow the instructions here to log in and set your name servers to ns1.wix.com and ns2.wix.com:
It sounded like you had issues with this step before, so just let me know if you continue to have a problem.
After that step is complete, you'll want to return to your Store on that blog, and purchase the Site Redirect Upgrade. You will fill in your custom domain to redirect your site.
Just let me know if you have any questions or run into any issues!