I have a Mid-2009 Macbook Pro 15' 2.53GHz Intel Core 2 Duo, 8Gb Ram, 250 GB HDD. I'm very interested in upgrading to a June-2012 Macbook Air 13' 1.8Ghz, 8Gb Ram, 128 GB SSD. Would I see an increase/decrease in performance? I'm only a basic user that does primarily web browsing and *light* gaming. I'm also a student so portability is very important to me. Thanks for the advice! Also, what would my macbook pro sell for?