Try using the migration assistant, from utilities, and point it to the shared drive where you keep your time machine backups.
@Baloo: I think it asks you during the process, but don't quote me on that. Either way it shouldn't over-write, so you can restore a big chunk, and just delete it later.
If you want to access it as a drive, log in to the computer that the Time Machine backup drive is connected to, then navigate to
/Volumes. You should be able to see the Time Machine backup drive.
If you open it, you will see all the different files from all the different computers you have backed up to it. These will be called something like
<computerName>.sparsbundle. If you double click on one of these, it will mount the sparsbundle as a drive. (This is the drive you see when the Time Machine backup drive shows up on your computer when you are performing a backup.)
sparsbundle belonging to the computer you are interested in. (It is best to do this from the computer that is physically connected to the backup drive, because otherwise it will take a lot more time.) Once the
sparsebundle mounts, you will see a folder called something like
Backups.backupdb. Open this, and inside you will a folder with the name of the computer that owns the backup. Open this folder, and you will see numerous folders, with dates for names. Open the one that interests you, and you will be able to navigate the filesystem as if it were the actual computer.