World of Warcraft HIGH latency issues

As the title says, as of the last week, I am experiencing some insanely high lag, I used to ping at like 300-450 ona normal day. Lately I am way over 1300 and sometimes I can get it down to 800. Now I understand a little about wireless networking but if you tell me like step by step on where to go and what to check I can do it, all I know is it makes the game insanely difficult to enjoy. Can anyone give any tips? Lets see, we have 2 laptops, an Xbox 360, and a desktop on one wireless router, but my box is the only one CONSTANTLY on all day/night. What do you guys need to help me? And as always, you guys rock...all help is appreciated

NEone? Plz...