My suggestion is to take it to a service technician and ask them to carefully remove the hard drive and put inside a 2.5" Firewire hard drive case such as the ones from
http://www.macsales.com/
That way, you'll have control over the hard disk.
Maybe even get that case first.
http://www.apple.com/uk/buy/ has a listing of authorized service providers who can do it.
And when you are done, you can use the migration assistant to reimport the data back that was in that drive.
Be careful not to drop that drive as the cases don't take a beating that well.
In the future always backup your data as my FAQ explains:
http://www.macmaps.com/backup.html