Your best bet is to post over on the official tech support forums. Either the forum technicians or one of the volunteers will ask you a series of questions about your network information so that they can easily assist you further in helping you fix the issue.
Before you post though, read the stickied post at the top about the forum guidelines. It will save you a lot of headache and help you to post a thorough help request.
http://us.battle.net/wow/en/forum/1011701/