Ok first things first,
your machine uses a AMD processor, it is 32bit, the processor is 1.3ghz, it is not a performance machine.
adding memory will add performance since your PC uses an ATI chipset for video memory, your system uses shared memory and can pull up to 1.4gb of memory to run high graphics, adding 2gb of memory will add noticable increases in performance if you do a lot of video, picture, movie watching, or editing. If you just browse the web, you will not notice any difference. your machine comes with 2 1024 (1gb) SODIMM memory sticks, you will need to buy 2 DDR3 PC3-8500 SODIMM 2048mb sticks to install on your machine.
To Lcristia,
You are mistaken,
your machine will page anyway,
windows by default uses a page file, in a laptop, most desktops your video memory if onboard is included in that page file, you can turn this off, run a systeminfo check and you will still see a page file. This is windows way of using a Swap file off the hard disk. You can run 16gb of memory, you will still see a page file.
Your hard disk is a 5400rpm drive,
you will add memory, you will see a bottleneck effect, adding a 7200RPM drive will void performance increases after memory upgrades, but keep in mind that the AMD processor in your machine is not designed for mind bending performance.