Alfadiag is a great tool you can use to connect to the OBD-II connector. The software can be purchased from:
Alfadiag.net
A cheap OBD converter is avalible at, look at the recomended adapters on the alfadiag site:
ECUFix.com
I've used the alfadiag software on my 147 GTA -03 toghether with a serial->OBD adapter and it works great. However, make sure you have a serial port fitted to your laptop since most USB->Serial adapter does not support the required baudrates.
Hope this helps,
/Karl-Johan