just order broadband from your choosen ISP (there are hundreds to choose from) then cancell your dialup account.
Unless you wish to keep your existing isp who should be able to migrate you to a braodband account depending on their systems.
http://www.samknows.com/broadband/checker2.php
gives you an estimted speed you'd get (and it is just an estimate) but also tell you which LLU providers are in your area.
I suggest you read reviews.etc to help you make your choice.