Hmm... that is just how SWMBO's problem started, more or less... It gradually got worse and developed into squealing, followed by grinding!!
Sorry to be the bearer of bad news, but, if you go onto my post 'new clutch time' it is all there in gory detail.
It sounds, to me, like the release bearing is on its way out, do you know how old the clutch is? the bearing is a pretty flimsy design imho and as soon as the noise started, it did not last very long.