Time for a new clutch?

[Welsh Dan]

Hi.
Been noticing a few problems with the clutch/gearbox recently. Mainly was problems shifting into fifth, which was intermittent. Anyway, on the way back last night, all of a sudden when I put my foot down a bit more the revs would rise to 5k, and the car would slowly accelerate. As I got closer to home it got worse and worse, to the point where it seemed to slip with very little throttle. Parked it up, hoping that it might go away in the morning, (which funnily enough it hasn\'t) and now I can\'t get it into any gear whatsoever.
Assuming that it is the clutch, how much am I going to be looking at for a standard replacement clutch, since its sunday and nowhere is open today. I\'ve checked the cable and that seems ok, as does the fluid levels?

Thanks

Dan