Pfui - 7:38 am on Jan 3, 2011 (gmt 0)
1.) I'm unfamiliar with that IP belonging to any known bot, and definitely not one of the majors. Regardless, if any 'visitor' -- bot or body -- is hitting hard enough to slow down a site, it's blockworthy.
That said, if you don't have access to your logs, the IP may not have caused the slow-down...
2.) How did you confirm that IP was the culprit?
3.) You can do your own WHOIS lookups through major registrars and countless sites like dnsstuff.com, domaintools.com, etc.