Clutch pedal does not come back up and having trouble putting car into gear on a fiat stile, 2004?

Yesterday, whilst driving, my clutch pedal was staying down once used and I was having to pull it back up with my foot. I have tried it again today and the pedal is all the way to the car floor and I cannot put it into gear whilst the engine is running. My other half looked under the bonnet and thinks that there is a leak somewhere as we can see wet patches. Neither of us know anything about cars and was just wondering what the problem could be and how costly!? Many thanks.