ASUS F3JC RAM Limit

Most of the notebooks I see of your model have Windows XP installed, which should thrive on 1GB of RAM. If you have Vista, consider upgrading, but if you have XP, consider using the msconfig utility to change what programs start with the computer to decrease the amount of RAM used by the system just from the start. That is, of course, unless you want the RAM for another purpose.

Your processor is likely to be upgradable, whereas your graphics card is likely not. Some Asus units are known to use MXM slots for graphics cards, so you may have a chance with this notebook. Take a loot around here:
http://www.mxm-upgrade.com/