There are lots of place that do what you want. Search for online backup in Google.

It's definately not going to be cheap however. You may want to consider clubbing together with some other people and just buying a coloc box and shoving a large HD into that. It'll be cheaper per MB than the online backup places but you'll lose the ability to have it backed up regularly.

The bandwidth issues shouldn't matter even though you've got a large amount of data as you're using it as backup and you're not going to transferring 10GB every week.