Agh...the cyan...it hurts my eyes.
Anyway, as always I'd recommend a new build from scratch, but if that isn't an option than a quick graphics card update could do wonders for you. Thankfully you have a PCIex16 slot so any card you buy can easily be reused at a later date should you upgrade the motherboard/CPU.
Primarily you need to found out: A) How much you want to spend and B)What your current power supply can support. Then we can make an informed decision on what GPU would be a suitable choice.