What could be wrong with my network or ISP?

First some specs. ISP: Dodo Australia, Router: Netcom something or the other. OS: Windows Vista

In the last week, I have noticed increased trouble with World of Warcraft. Now, I am pretty sure the problem is not on Blizzard’s end as my girlfriend plays the same server just fine. However, most of the time when I try to connect now, I get “Disconnected from server” immediately and have to renew my DNS cache, or more commonly, my ping soars over 8000… and I’m getting sick of it… Does anyone have any advice that can help me get to the bottom of this?