If your upload takes months, I'm not sure that _any_ online backup is right for you. I did a fresh install recently, and I've got 84 GB backed up. It took me a couple of days, and that's on a cheap ADSL line in The Netherlands.

In your case, I guess it would be much better to look at other solutions. For example if you have a Mac, get an extra Time Machine drive and put it at your employer's place. Every week, bring your laptop there and back it up.