By the time you spend $70 for more memory and $100 for more batteries, you could have just bought a better laptop overall for $700. Just wait. THere will be plenty of better deals, even locally, in the next month before you have to go to school.
BTW, Centrino is a combination os using a Pentium M processer and Intel's wireless ethernet card. There are Celeron M and Pentium M centrinos. Centrino isn't that important, but Intel Mobile processor is. The wireless card doesn't matter as much for power consumption.
FWIW, my 2.75 year old Dell 600M has a Pentium M 1.6GHz, 512MB RAM, 30GB HDD, 64MB dedicated video memory, CDRW/DVD-ROM, 1400x1050 LCD screen, and a 6-cell battery that lasted at least 2 hours with heavy wireless internet use during my classes I took up to April 2006. If I disable the wireless adapter and lowered the brightness I could get another hour, but my classes were only 2 hours long. I always recharged when I got home at night. So, batteries only lasting a year must apply to some crappy laptops. Oh, I paid $742 for it new and it has better specs than this Gateway you listed (except HDD size). I'd expect better performance for less money some time a couple years later, even if mine was a hot deal at the time.
