Car problems

OK I've put extensive work in to my car and would
hate to give up...when I start my car and try to back
up it goes no where fast like its not getting enough
power to go over the hump of the drive way..but if I
start the car put it in reverse and press the gas and
come of the break a Lil it get enough to get out
then when I put it in drive I have to stay on the
brake and gas or the car will shut off.but once I put
in drive it seems to run fine