No worries. I don't really want to advertise for one or another and I'm not sure if it's against the rules or not here so I won't. I've used a few in the past and you can find them pretty easily by searching for them with Google. A lot of the time they also offer a trial account, so you can use their service for a few minutes before it disconnects you just to see if it'll improve your latency.
250ms+ without tunneling is pretty decent. You can probably shave a few ms off that with a tunneling service if you think it'll make a difference. Best to try it out and see for yourself, and if you have any doubts, you can always give the Blizzard hotline a ring or send a ticket and ask if they're ok with it. They're really helpful.