Kev, you should get a new processor and then more RAM if it doesn't suit your needs. Processing is carrying out tasks asked by a program, here, this is how I've compared a computer to the human body before:
The processor is the brain. It does the thinking. It is the common sense. It allows you to move at your own speed, depending on the processor, you're smarter or dumber.
RAM is sort of like your maximum brain capacity. Your brain size determines your brain's overall maximum power, and the stress that's put on your brain.
Your harddrive is memory and what you remember, etc etc. It's all of your stuff.
I know they're not 100% exact but they're comparisons to an organic living thing, really, what do you expect.