Buying a good graphics card and some more ram will set you back a substantial amount.
If you do have an AGP motherboard, you might want to consider saving up for a PCI-E motherboard AND a new gfx card and do it right.
You can only upgrade a system so far.....every once in a while you have to spoil yourself.
Not only is PCI-E the norm nowadays...these cards are somewhat cheaper than their AGP counterparts and you get improved performance.
If money is a big issue I'd go for the better GFX card....it looks to be the weakest link on your rig.