Issue with sub-domain installation and new domain name

Hi, I originally had wordpress installed on olddomain.com. I wanted to update the theme but knew it would take a lot of tweaks and changes, so I decided to install wordpress again on olddomain.com/new and import everything from my old blog there to work things out at my leisure without disrupting the current site and having all of my changes visible to the public. Once I was satisfied with it, I changed the web address in my dashboard to olddomain.com (while logged into the WP account for the sub-domain) and that seemed fine. However, as part of this upgrade, I also wanted to change the domain name, so I did the permanent 301 re-direct to my new domain and changed the web address in my dashboard to newdomain.com. The site looks fine, but I’m running into all sorts of issues. For one, some of the icons from the new theme won’t show up because the host theme files are in the old domain and not the new domain. Also, when I try to live preview posts, I keep getting an error saying I don’t have permission. What should I do? Any help would be greatly appreciated! (newdomain = adiaadores.com)