in that regard just ask one of the admins how the selection of the host location works.
usually the admins hang out in the main channel and their names are blue or post the situation in their forums under "technical support" and/or "suggestions". your login and pw should be the same on the website as for your "bnet-w3arena" login.
edit: just to compare i have 8 ms ping on europe-server and ~100 ms for the us-server somehow i end up getting games on the european one all the time.