does the transmission go into gear at all or is it locking you out of all gears? is it making any noise? are you sure your clutch is even hydraulic? are you sure you bled it right? have you attempted adjusting it? what does your fluid level look like? sounds to me like a hydraulic problem (or broken clutch cable if not hydraulic...)- the clutch isn't disengaging.

but as for your original question, you don't have to replace the clutch disc and pressure plate when you replace the throwout bearing, but it would be a good idea if you had the money to go ahead and do it while you've got it apart.