Help me fix my Magento Store with Error 503

I was just setting up my Magento, it works fine for the past couple of days, but today, I decided to delete Moneybookers extension from Magento connect, it was fine for the first 10 minutes then suddenly it went "Error 503 Service Temporarily Unavailable The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later." I thought it was because of the magento connect connection. Bcs I set it "website offline when modifying". But after an hour, it's still like this. I couldn't access admin page neither the front page. Modifying files from FTP access wouldn't do the job for me as I know nothing about Magento structures and all. It would be great if anyone could help me. I'll give you the access to my FTP.