Looking for User Points/Cash/Karma Plugin

I am looking for a plugin that can be used to track user points/ fake cash etc.
Like for each post by a user, he gets 10points and for each comment, 5 points and for just reading the post 1points.
Once a user reaches a certain threshold we can possibly upgrade his account previleges etc like from subscriber to contributer..
I am new to wordpress. I have seen many mods/plugins for forum software like phpbb or ipb or vBulletin but could not find any for wordpress. please help me locate one if there..

thanks in advance,
rakesh