Engine cuts out

sometimes when i first start the engine it revs up high with out me touchin the gas then drops, the car begins to splutter then the engine cuts out, if i even attempt to pull away before it cuts out the steering gets heavy then the engine cuts out and the steering locks, i can only just about afford to put petrol in never mind find a mechanic, if anyone can give me any ideas as to what it could be id be gratefull, im a woman so not familiar with mechanical terms so pls keep it simple lol thanx xx