Julius, you can use
NewEgg's Memory Finder Tool and just click through to your specific HP Pavilion laptop model. NewEgg has some really good folks on their payroll so I'd expect it to suggest actually compatible memory.
NewEgg does hold shop in Oz and ships from in-country there. Their tool should help you no matter where you choose to get memory, though.
You might also refer to this
HP support page.
Also, let's leave the open source
xserver-xorg display driver in place for now. It does work quite well. When your semester (term) ends, then venture to add the proprietary driver from AMD. You will want to open Synaptic Package Manger and install
fglrx, and reboot. It will likely improve your graphics performance. But let's not make any changes like that amid your current semester.
