I drove my car down hill on third gear to slow the descent as soon as I got to the bottom of the hill the car turns off and won't start again. When I try starting I can hear the starter but the engine is not turning over at all -i just get this cranking sound that's sounds weak and over the gears.help - I spend 150 $ for tow and now am stuck .

Check and recharge the battery if needed.
I don't know what exactly you mean by "weak" and very confused about "over the gears" reference.