Renault Laguna 04plate Problem with gears/clutch?

My Renault Laguna has 90,000 miles on the clock and has recently developed a major whine in third and fourth gears - mainly only when under acceleration (no matter how heavy or light)

Also it is having problems going into reverse (usually I remedy this by inching forward a little then it goes in fine) and when you do reverse, and you depress the clutch the car stops DEAD (Like when you jump start it)

Could these two problems be related, what could be wrong, how hard is it to fix and, more importantly, how much will it cost me??!!