I have a Macbook Pro 17inch. I use Propellerhead's Reason 3.0 software program. For people who don't know what that is, it's a MIDI program to create music and artificial sounds.

I haven't had a problem running Reason 3.0 until recently. The more effects and sounds I add into the program, it begins to slow and it reaches a point where Mac's popup says the computer is too slow to run the program. What do I need to buy in order to prevent this?

I'm guessing I need more memory or hard drive space for it. How will I be able to add that if it's a laptop? Or if that's not the case, what do I need to do to keep it running without it slowing it down or shutting the program all together. Thanks in advance.