Try doing a compresion test on each cylinder, you might have a bad rings or piston, good luck.

Does the engine smoke out the tailpipe or just under the hood?
if it sat for two years you could have stuck rings. you might try pulling out the plugs and pouring some top end cleaner or transmission fluid into the cylinders and let it sit over night.
be sure to crank the engine over a few times befor you put the plugs back in. put a towel over the plug holes to keep the  fluid from going everywhere. I have seen engines that have sat for a while smoke for weeks and then just stop ( i dont ever get that lucky)
good luck

Check the PCV system.

A broken ring can do this. 

update on the problem...

It's now smoking out of the dipstick tube, and is seeming to be going down a cylinder. It's starting to sound like it's on only 3 cylinders, but all the plugs are tight, and wires are on there good.

Is there anything I can do to extend the life of this engine? I don't have the money to get it replaced, and it's starting to get hard to start the car.

I had a smoke problem so I put in some trany sealer into the oil,next day the smoke was gone.but if your rings are shot try using diesel engin oil,some good thick stuff it may help.Larry

WAIT!!!!!! Before ya start pulling the motor, try this really simple thing that an old Pinto junkie taught me: There is a tube (rubber hose) that comes off of the oil filter mount that goes up to the PCV system. Back in the day (I.E. 1970's) these were notorious for clogging up with gunk from the oil and gasses that pass through it. Take all the tubes and hoses off of the PCV system and clean the heck outta them. The way you described your situation is identical to what my car was doing (PCV filter, air cleaner and valve cover coated w/oil). I tried this 'cleaning' on my own car and it helped a bit but the engine was too far gone. But, give it a try!! I've talked with the oldest mechanic at our shop (And I do work at a Ford dealership. Roy has been with us for 25 yrs.  The first 'New' model Ford that he worked on was a '64 T-Bird) and he agrees. I wish I would've known about this trick years ago. Like I said, give it a try, and please, let me know what happens. I'm curious. Good Luck! Robbo II