Noisy in all gears except for 4th is generally a good indication that the bearings inside the tranny need replaced. If you can do it yourself, you can buy good quality bearing and synchro kits for under $150, off of ebay....or I think some vendors carry them too, for just a little more than ebay. If someone else is going to have to fix it, then I have no idea what it would cost.
A bad throw out bearing should only make noise when you push in on the clutch (that is when it is spinning). When the clutch pedal is up, then the bearing is not spinning (or shouldn't be, if the clutch is adjusted correctly) and won't make any noise, no matter if it is good or bad.