I would definitely be interested in upgrading the memory capacity, but how would you do that with a machine that is as compact as a laptop? I'll probably go troll around google in a second but maybe you know of a way to add external RAM or something else?
Memory cards are available for most laptops, just as they are for desktops, and at reasonable prices. (One exception I can think of is that DELL has, or had, a condition in their warranty that if you opened the case the warranty was voided. I don't know how ASUS spells out their warranty, so you need to check that first and decide if your warranty matters to you.)
It is probably better for most novices to get help at a store that has computer technician assistance available, a store like Staples is one example.
Memory in Laptops and Desktops are plugged into slots on the motherboard specifically designed for them. You need to match the memory cards to the type of memory cards supported by your machine. You also have to check to see if you can simply add cards or if you have to swap them. If your PC has two memory slots and each is slotted with a 2G memory card, then you will have to replace one or both of them. If your PC has 4 slots and only two are in use, you may be able to simply add another card or two. Be careful to check the requirements of the motherboard to make sure what combinations of cards it supports, and what slots support which sizes.