Hi lyriks i got. Welcome to H-kon.net
Just a quick post before i head out the door.
I would open your system up first to see if you have an AGP or PCI-E port available. You need a separate graphics card in there. Then, i would at least upgrade to 1GB memory total, perhaps 2GB if your motherboard supports it.
I can take a look at it tomorrow around the same time as this post as i am going on a little christmas binge

Hardware recommendations on the cheap will also be posted.
Your system would benefit from more memory which i would buy first. 256MB just isn't enough these days. Your processor is just waiting more than it it is working with the memory amount in your computer. You should at least see a 40% increase in system performance in general with more memory.