Ideally you need an ISP that will offer a cron service. At the same time, I think that once per hour is not so bad, and first of all you should apply for it Ipowerweb will do it if they say they will do it.
If you cannot figure out how to work out the German online cron, then there is a windows option, which you could install on your home computer and it would work if you keep your home computer on all the time.
I tried to find the one that I was thinking of, a program that would run on a normal home windows computer. I came accross this, but I am not sure if it is appropriate since it is probably for windows servers. But please check it out. And also search for windows cron on the forums.