1. How frequently Google is updating the SERPS based on panda?
Answer: Google never mentioned anything about the time at which an update can happen. So it can happen AT ANY TIME.
2. Is the penalty confined to a low quality page or whole website?
Answer: site wide penalty.
3. Tips on how to recover from the Google panda.
Answer: Make sure that you create a unique content and information for the site visitors and not for the search engines.
4. Is the penalty permanent?
Answer: NO it can be corrected by trimming down the low quality content and by correcting the errors in the site settings and so on.
5. Till now how many updates have been made?
Answer: approximately 24 updates are done till now. And there is no idea when will the next update happen.