If your clutch is slipping then you most probably need a new one. It's a pain, but it is do-able in your garage.
If you have the other problem, you're in luck. Your Toy uses a hydraulic clutch mechanism. Your clutch pedal activates a master cylinder (like your brakes. That master, in turn, pushes a slave cylinder (basicaly a big wheel cylinder that dinengages the clutch plate.)
Unlike 99 % of vehicles, Toyota trucks use a hydralic slave cylinder that mounts outside the bellhousing. So you don't have to tear your tranny out, just to change it. If you are having trouble getting your truck in gear, either the master or the slave is bad. You can try to bleed the system, but you'll almost always need to replace one or the other. I recomend replacing both. That way you know you got the right one. The price is not all that bad for those parts either. It's a simple r + r.
To bleed the system, just pump the clutch pedal, hold it down, and release the bleeder on the slave. Just like brakes. Do that a few times and you should be back in business.