ditch the usb modem.
I use a wireless modem router, and tiscali.
That said, I wouldn't recommend tiscali. low bandwidth, high retention ratio, their customer service is atrocious.
unlimited, is not unlimited. they cut me off when they incorrectly charged my payments to someone elses account. There are a lot of other horror stories out there. utter crap.
I am changing provider when I move.
If you have a choice, don't use them.
(I can't afford to lose internet for the 10 day changeover period)