Vauxhall Corsa loud droning noise

Please can anyone give me any ideas as to what the loud droning noise could be on my daughters corsa. The noise is not there when the car is stationary but appears once you pick up speed.I assumed it was the exhaust blowing but took it yesterday where they replaced end piece.Although it now sounds quiet when standing once you pick up speed the noice seems to get louder.It is coming from the front of the car and sounds like a combination of a diesel engine with a blown exhaust!!I was told yesterday the ofs drive shaft needs looking at, which is causing a clanking noise when its driven over bumps etc...My daughter is taking her test tomorrow and will be gutted if she cant drive the car if she passes..Any ideas of what it could be and how much it will cost to have the drive shaft (and new problem) replaced please..Many thanks.