metering?

ok /prog/ first time here..

how would i make a program that goes to my ISP's site, logs in gets the "usage meter" data and brings it back to the application?
ie, i want to make a metering program that also warns if im getting close to the limit

i can code C++, but thats probably about it..

- cURL
- Regular expressions
- Any decent scripting language (Python, PHP, Perl)