Ok heres the situation, I have a stingy character who doesn't want to spend more than R1000 (thats roughly $120) on her setup. And even better if she can not spend anything at all! now she is running on an HP dc7100 2.8 P4 ht with a (please, brace yourselves, I nearly choked when I heard this) a PCI -as in not agp or pci-e- FX5200... now I told her that there is no way to actually upgrade this thing since the case is so small that nothing but her low profile FX5200 (which I had to hunt around for) will fit in her case. She just uses the machine for animation, rendering and occasional mild gaming, but she would like some extra performance. So I went to overclocking her GFX card. The dc7100 has surprisingly good cooling capabilities and I managed to clock it to get a score of about 116 on Video Card Stress Test (it previously did benched at 79). the problem is it doesnt overheat when I clock it higher (the gpu or memory) then it just goes slower. what is missing here?

Use RivaTuner to OC it. The OC sometimes doesn't stay with CoolBits or other programs but with RivaTuner it mostly does.

A low profile Radeon X1300 PCI card would have been much, much better.

And where would I get a low profile X1300 PCI card?

I don't know where you live, but some Froogle search results are here.