My questions are: 1) Where to buy it and what to buy? I have heard that this RAM is generic enough and it does not have to come from Apple. 2) Can I reuse my existing stick(s)? Would I have a single 2GB module, or 2 x 1GB modules? 3) If I have 2GB already, is it a good idea to have one old stick and one new one? Which one is better placed at the top and which one at the bottom? Let me know what questions you have. My computer's info:

Hardware Overview:

  Model Name:   MacBook Pro
  Model Identifier: MacBookPro3,1
  Processor Name:   Intel Core 2 Duo
  Processor Speed:  2.4 GHz
  Number Of Processors: 1
  Total Number Of Cores:    2
  L2 Cache: 4 MB
  Memory:   2 GB
  Bus Speed:    800 MHz
  Boot ROM Version: MBP31.0070.B07
  SMC Version (system): 1.16f11