Non-root data transfer monitor

[theforce]

Hi

I need:
- to monitor my own internet data usage (or "bandwidth utilisation" or "bandwidth usage")
- not involve sysadmin (No root applications, no compiling!!!!)
- firefox extension would be nice?
- shellscript?
- gnome app?

My situation:
- I am ubuntu user, BUT question relates to work which is CentOS :(
- Work on server as gnome desktop user without root access.
- We have limited data usage for internet access with our isp
- My data usage is mostly through firefox
- We do not have iftop or iptraf installed.

I have looked:
- google
- firefox extensions (only one that fits the bill is which is windows only)

I have only found non applicable:
- windows extension for firefox
- root access needing applications for running/installing


Hope it's possible.

thanks