hacked wordpress without solution for long time

Hello guys.
I have a big problem and tried so many things. Now i don`t know what to do more.
I have http://www.otvlive.org . It was an older version before, not it is 2.7
5 months ago from nothing there appeared a lot of pages .
I have checked with site:otvlive.org .
An example is http://www.otvlive.org/index.php?Zerit/ .
Unfortunately now there are 10.000 pages from this script which is slowing my site and maybe i will have a problem with the new hosting company.
What i did. I have seen 3 tables more in the database and i removed them. Nothing in wp index.php, nothing in theme, nothing in plugins. Also i have changed the theme/hosting company/ upgraded.

Can someone help me please?