Can i extract from my iPhone browser the history older than 8 days ago? It looks like that the data older than 7 days are automatically wiped from the iphone.

What's the database that stores that data, in case one exist, so that by jailbreaking my iphone i can have direct access to it and hopefully, extract the data i need?

If i did this yesterday, i would not have had this problem... :(
You're looking for var/mobile/Library/Safari/History.plist. Try looking in that file, but I'm pretty sure Safari itself will only store the most recent seven days of data in that file, though. You'd have to make a tweak that modified Safari to extended that time frame.