python exec when imported script has other imports -

i have script:

from myhelperfunctions import * # parse arguments args = docopt(__doc__, version='mainprog 1.0') myhelper1(args) ... 

this script else maintains , have no control over, cant modify it. script structure looks /opt/app-to-import/{main.py, myhelperfunctions.py}

i want run code in program in home directory, don't want start new process. tried exec() , imp.load_source() load , run inside same process. every time complains saying no module named myhelperfunctions. right way this? using python2.7.