Malware attack on Inkygirl & my sister's site :-(

I was hoping to be writing up a report about the fun I had at Errol Elumir's first housefilk (see my burry iPhone pics of the event here) but instead I've been trying to fix my Inkygirl site and my sister's site, which were hacked late last night.

Very frustrating, and I can't login to make a backup, delete plugins, clean up the account. Advice appreciated. Changing the passwords on all my accounts...