You're on the wrong track. You need to transform the equations you have into a set of equations that clearly define a helix.
Try rotating the coordinate axes clockwise by around the z-axis.
The substitution is:
and of course .
And you'll need to know that a helix is defined by a particle traveling at a constant rate in the z direction, and around a circle with constant angular speed in the x-y direction.
Post again if you're still having trouble.