Windows 7: internet usage

i'd like to know my monthly combined (ul & dl) usage of my internet as a whole as my isp would perceive it. i have 2 computers on my network. can windows find me this info?

if i can only do this for one computer, it's not so bad, i don't use internet much on my other one.

You can try this:
Broadband Download Monitor - Free software downloads and software reviews - CNET Download.com

For two machines just use it on each of them and add the figures together.

for assistance adding type "cal" then [Enter] into the start menu.