Most data restoration shops can restore data which has been deleted off of the hard drive of a computer. It all depends on how the data is deleted. If the file has just been deleted then the data can usually be recovered. If the file has been overwritten with another file then it probably can not be recovered.
As for tracking IP addresses, you can use whois.com to find out who owns the block of IP addresses which the IP belongs to. For anything more specific you would have to contact the owner of the IP block.