Need help. Transmission went south this pass saturday.

Ok here goes. I recently purchased a 1986 N/A 300zx two weeks ago. After driving the car around locally, I deemed it roadworthy. So I'm traveling down 95 south,on my way to a date. Once it switches over to 85 south and I get close to southhill va, I smell a funny smell and hear my tranmission making noises while I'm cruising in 5th. I pull on the 15 south bound off ramp and cut the car off. Once I cut it back and let off the clutch, I notice that my transmission it making a whirling noise. I find out that I can't shift any gears from 1st to 4th, only 5th and reverse as if the transmission is locked. No matter what I do the car doesn't move. Someone told me that this is because of a worn throw out bearing and once I replace that and install a new clutch, I should be in the clear. I can say this, that when I press in on the clutch it doesn't have that engaging feel it would normally have. I remember when I first got the car that from time to time when I shifted it that I would hear a slight chattering noise. I dismissed this as a loose heat shield and thought nothing of it. If anyone could clear up this matter for me, it would be highly appreciated. Thanks!