What server are you on? All WoW US servers are located in the US, even the Oceanic ones. Playing on an Oceanic Server or a US Server is no different if you're looking at physical location.
Play depends on :
1. The Streamyx IP you're connected on. WoW players hunt around for stable ones. I won't say fast coz it's still possible to raid with 512 kbps lines.
http://forum.lowyat.net/topic/4112682. Hardware - free HDD space, memory, updated video card. This is just to make the game move faster because Outlands is more graphically demanding than Azeroth.
3. Population of the server. Server location doesn't matter but if the server population is a lot, expect some lag. Note that US servers have larger population capacity than Oceanic Servers which are the older servers (but so far has been pretty stable compared to the newer ones that came online in the past year. Can check against the Maintenance Downtime notices).
4. Turn off any software that auto-updates. And check regularly for spyware and viruses that will eat up your bandwidth.
These are generic answers.