That battery life on that HP dm1 is pretty good, when i first tested it it lasted for 7~ hours - this is with low battery properties. If you're not using the net turn off the wifi, bluetooth etc
You would want to make sure the unnecessary background programs are turned off from startup so the only things that are running are word, adobe, chrome etc.
If you're at uni browsing the net and doing work w/o a charger the battery will still last a solid 3 1/2 - 4 hours, provided it's on battery saving option.
At melbourne there are heaps of power points esp. if you're in the library or commerce buildings.
I normally only bring my laptop if i have a break during the day or plan to stay back after my classes are done. I don't use it for lectures, i stick with the lecture slides printed out and annotating them.
Check centrecom:
http://www.centrecom.com.au/catalog/default.php they normally have a wide range of laptops. I actually bought this beast - Asus N53S: 750gb HDD, 8gb ram, i7 (2nd gen), 1gb nvidia graphics, 17inch for $999 after christmas! It's bloody amazing, i intended to use this for uni... LOL. I took it to uni most days for like 3-4 weeks and just gave up. It was too heavy and i didn't want to risk breaking the hard drive or anything by lugging it around everyday.