help!91 automatic 3 speed jetta doesnt shift into third gear

i need a cheap solution to fix my transmission,all levers/cables are fine but it wont upshift into third gear,if i cant resolve this cheaply in the next few weeks i'll just go on the highway and shift it into reverse and end this problem once and for all,it's driving me insane.:banghead:

If you are REALLY lucky, changing the fluid and filter may help. Check the solenoids - you'll need a manual or to take it to a shop.
If changing the fluid and filter doesn't work, I'd take it to a shop. Problems tend to get worse if not taken care of in a timely manner.