Sounds like you don't have /etc/resolv.conf setup correctly.
If you can ping IP, but not DNS name, then DNS is not setup correctly.
You'll need to know the IP addresses of their DNS servers; usually a pair.
You could try this page, scroll down to Linux section http://www.howtogeek.com/howto/7406/...le-public-dns/
You could also search here at LQ; think I've seen this qn before somewhere.
Good luck & Welcome to LQ