first check the level of the fluid.top up and bleed if required.
if your p/s pump is starting to make noises then it is coming to the end of its life especially if it is the original, there is a refubishment kit available for it, but it may be beyond an amateur to fit without workshop facilities,however taking the old pump off and replacing it is not difficult, but it is imperative that the air is bled out of the system after refilling the system with fluid, this can be done by running the engine and taking the steering from lock to lock at least twenty times or untill all the minute bubbles stop appearing.
I appreciate your advice. I'll give it a go this week and let you know how it turns out.