When the car is cold the clutch will slip between 2000-4000 RPM. But when the car warms up the slipping will stop and the car will run normal again. What do i do?

The Haynes manual tells you how to see how much clutch you have left.

Most likely though, you have oil on the disk from a leaky flywheel seal. Any oil puddles you didn't mention?!

The manual says that there is a hole in the bellhousing where the clutch slave cylinder hooks up. Measure the rod you see in the hole. if it's
1 1/2 inshes long, you need a new clutch.