I'll give a suggestion, but others may come around with something better.
Do you have a Windows disc? I would look into performing a repair installation just to see if you could get back into Vista to retrieve the data.
Once you're in, back up all of your files to an external HDD. Once the re-installation of Vista is complete, DISABLE auto-run. This will allow you to plug the HDD into a usb port, without the virus jumping straight back over. Scan the externall HDD with a malware scanner of your choice.
I would personally recommend MBAM for this (The free version is good enough) www.malwarebytes.org