How do i fix my clutch on my 1.8 Diesel Fiesta?

Hello guys, hope you can help. I have got a P Reg 1997 Ford Fiesta, and the clutch biting point is really, really high. When i set off the car rev's really high with no performance coming from the engine. Its makes a lot of noise, but there is no speed. (sorry i am rubbish with cars so my explination is not fantastic). The clutch i believe is to be Hydraulic, so it can't be adjusted. I really can't afford a new clutch so i am looking for tips to fix my car without replacing the clutch. Thanks