2000 Vauxhall Astra vauxhall astra mk 4 - burning smell, loss of power up hill and stiff braking

hi, my partner's vauxhall astra (mark 4) is experiencing some problems and we would be grateful of any help possible :)
over the last couple of weeks the engine has appeared to get louder, and tonight when travelling back from work there was a really strong burning smell (like plastic/electrical) we couldnt see anything wrong when looking at the engine (although it was dark!) but you could see smoke in the headlights. the car just wouldnt accelerate up hill at all and the brakes seem to be a little stiff. we also noticed a slight wirring/squeking noise when the car was moving. any ideas as personally i know very little about cars :s thanks