scammer got me! help

I had a strange thing happen today. sombody accessed my ebay account and fraudulently listed a car for sale using my username. They racked up $176 in listing fees. I got a email from ebay notifing me that they suspended my account and reversed the listing fees because they relized is was a scam. My question - How could somebody get my password? Ebay is saying I could have responded to a phising email. I know I didn't do that. I recognize those and don't ever respond. I also know my password is unique and somebody couldn't just get lucky and guess it. They are saying my email account through mu ISP could have been compromised and they requested a password through the forgot password procedure. Yet, they don't show a password request. Lastly they said a virus could recorded my keystrokes. I would like your opinion/idea on this and what steps I should take. I have paypal accounts etc, that I need to protect. This is scarey stuff. BTW- they listed a 69 camaro with a BIN of 6400. I never saw the actual listing. Any ideas on how this was done? I see those scam ebay auctions all the time and think who actually loses their user id and now it happened TO ME!