Help needed with car problem?

When going up steep hills I accelerate for more power and engine revs but car takes a few seconds to respond, just as if I was driving an automatic and it is changing gear. I do not lose speed, just takes a few secs to go faster. I had this problem a few weeks ago, when front brake was binding and getting hot. I had that fixed and it didnt happen again until yesterday but I noticed front wheel was hot again. My garage thinks that this is just a coincidence and that I need new clutch but I have no problem changing gear, or pulling off on really steep hills or holding car on clutch/first gear while waiting to pull out so I cant see problem with clutch. I have a Mitsubishi space star