Can I upgrade this RAM?

That's a 1GB stick of DDR-333 (PC 3200) (old DDR 1) memory. You need to know how much memory your motherboard can accept and what the largest module size that it can understand.

Either look up your motherboard on it's manufacturer's website or you could try something like the system scanner on Crucial's website: http://www.crucial.com/uk/systemscanner/

Of course though you don't have to buy the memory from them, you might get a better price somewhere else if you shop around.

find out what motherboard you have and check the specs online. there you will find the fastest ram the board will support without you having to change stuff in the bios. also the specs will say how much ram you can install