Urgent: Questions about DNSChangers

I ran some code from this question on Stack overflow... do not open the fiddle. I fear that it has changed my DNS. Here are some questions:

1. Does a DNS change affect one computer or all computers coected to the router?
2. I tried opening www.dns-ok.us but it won't load. Does this mean I am infected?
3. What other risks are involved with being infected?
4. Should I tu off UPnP?
5. Should I reset my router to factory settings?
6. Would a Norton scan be helpful?
7. Any more advice?

Thanks! :)