If I want to upgrade my RAM to 4GB, does Apple sell it, or do I get it from a site like Crucial? I really want Lion or Mountain Lion, but I just am not sure how fast it will run. PS- this MacBook is the model that came out right before the unibody MacBooks, and currently, with Snow leopard installed, it runs wonderfully fast. Also, If at some point the 120GB Hard Drive I have isn't enough, can I get a SSD drive? How would I transfer my OS and data? I have a time machine USB drive, but I didn't backup my system. Thank You!